EOTech Holographic Sight Parallax Induced POA Error Compared to Reflex Red Dot Sights

Milirad · Apr 14, 2024

Optics Tested:

EOTech EXPS3 holographic weapon sight
Trijicon Patrol MRO reflex red dot weapon sight
Holosun 530-RD reflex red dot weapon sight

Summary of Measurement Results for Parallax Induced Point of Aim (POA) Error:

Contrary to widely held belief, the EOTech EXPS3 holographic sight has about the same parallax induced POA error as compared to reflex red dots Trijicon Patrol MRO and Holosun 530-RD, which was surprising to learn.
The parallax induced POA error is between 3 MOA to 5 MOA for the EOTech and the two reflex red dots tested.
To see the measurement results and learn how the measurements were made, read on.

I hope some Hide members will find this useful. Please don’t shoot the messenger, the EOTech sights are awesome and many shooters love them including some of the most demanding expert military and LE operators. I did my level best to design and execute a basic scientific test for comparing red dot parallax error between different red dot models. It’s also pretty easy for others to repeat the test to see if others get similar results.

Introduction:

I recently purchased an EOTech EXPS3 with a flip-down magnifier because I thought it would have much less parallax induced POA error than my red dot sights. Two other motivations for trying the EXPS3 are that with holographic sights the center dot diameter does not increase in MOA size with magnification and the window size and FOV is larger as compared to most reflex red dot sights.

Parallax error in a CQC weapon is important in my view because shots are often taken under time pressure from highly improvised positions with a non-standard cheek weld or no cheek weld at all. The more forgiving the sight is with respect to where the dot is located in the window, the better. Holographic sights, including EOTech sights, are widely reported to have far less parallax error as compared to reflex red dot sights. Some of online and print sources even claim the EXPS3 sight is "parallax free".

This is the only reference I was able to find that has measured red dot sight parallax error results, and the results say that EOTech holographic sights are not parallax free but have significantly lower parallax error than most reflex red dots:

Comparative Study of Red Dot Sight Parallax | Green Eye Tactical

I'd like to thank you for viewing this report. It took a considerable amount of time to finish. I would like to apologize that parts of it may not appear formatted properly in your browser. Depending on what browser you are using- some of the images may not be visible due to the .tiff format.

www.greeneyetactical.com

Parallax Induced POA Error Measurement Procedure:

The first thing I did when the EOTech arrived was to unbox and place the sight on a stable aiming platform with approximately 9.5" eye relief for an apples to apples comparison with (1) a Trijicon Patrol MRO (MRO-C-2200018) and (2) a Holosun 530-RD (HE530G-RD). The test procedure for each sight was to center the dot in the middle of the window while aiming it at a grid target with close grid spacing, then move my eye side to side by the same distance for each sight (+/- 0.5”) and up and down by the same distance for each sight (+/- 0.35”) and then record the dot movement in inches on the grid. The target was set up at 7 yards which was far enough away to get enough dot movement for a reasonably accurate estimation of POA shift on the grid, but not so far away so that the grid lines were hard to discern at 1x. The smaller vertical eye movement as compared to the horizontal eye movement was to account for the smaller vertical window dimension of the EOTech as compared to the horizontal window dimension. Although the Trijicon and Holosun are round which would allow the same vertical and horizontal eye movement, the vertical eye movement was limited for all three sights in order to maintain a consistent comparison. This test procedure is not very rigorous, but the results allow for a reasonable relative “ballpark comparison” of the three sights. The results are definitely “good enough” to determine whether the EOTech parallax error is clearly superior or about the same as the reflex sights.

The bottom line - The EOTech has pretty much the same parallax error as compared to the reflex red dots, which was somewhat surprising to learn.

Another interesting finding was that the Trijicon has the smallest horizontal POA error when the eye is moved in the horizontal direction, and the smallest vertical POA error when the eye is moved in the vertical direction, but there is a translation of horizontal eye movement to vertical POA error and a similar translation of vertical eye movement to horizontal POA error. I have noticed this in the field when using the MRO but this is the first time I measured it and it was surprising to find that the horizontal to vertical and vertical to horizontal translation errors were larger than the vertical to vertical and horizontal to horizontal errors.

Measured results in inches of error for parallax induced POA error at 7 yards distance from the front of the sight to the target:

Approximate EOTech EXPS3 POA error induced by +/- 0.5” horizontal eye movement: +/- 0.35” horizontal POA error, negligible if any vertical error.
Approximate EOTech EXPS3 POA error induced by +/- 0.35” vertical eye movement: +/- 0.2” vertical POA error, negligible if any horizontal POA error.

Approximate Holosun 530-RD POA error induced by +/- 0.5” horizontal eye movement: +/- 0.35” horizontal POA error, negligible if any vertical POA error
Approximate Holosun 530-RD POA error induced by +/- 0.35” vertical eye movement: +/- 0.25” vertical POA error, negligible if any horizontal POA error

Approximate Trijicon Patrol MRO POA error induced by +/- 0.5” horizontal eye movement: +/- 0.15” horizontal POA error, +/- 0.2” vertical POA error
Approximate Trijicon Patrol MRO POA error induced by +/- 0.35” vertical eye movement: +/- 0.1” vertical POA error, 0.2” horizontal POA error

While the above error measured in inches are small for a CQC engagement at 7 yards, when the errors are converted to MOA they are substantial for 100 to 300 yard engagement distances.

Measurement results in MOA for parallax induced POA error:

Approximate EOTech EXPS3 MOA error induced by +/- 0.5” horizontal eye movement: +/- 5.0 MOA horizontal POA error, negligible if any vertical POA error
Approximate EOTech EXPS3 MOA error induced by +/- 0.35” vertical eye movement: +/- 2.9 MOA vertical POA error, negligible if any horizontal POA error

Approximate Holosun 530-RD MOA error induced by +/- 0.5” horizontal eye movement: +/- 5.0 MOA horizontal POA error, negligible if any vertical POA error
Approximate Holosun 530-RD MOA error induced by +/- 0.35” vertical eye movement: +/- 3.6 MOA vertical POA error, negligible if any horizontal POA error

Approximate Trijicon Patrol MRO MOA error induced by +/- 0.5” horizontal eye movement: +/- 2.1 MOA horizontal POA error, +/- 2.9 MOA vertical POA error
Approximate Trijicon Patrol MRO MOA error induced by +/- 0.35” vertical eye movement: +/- 1.4 MOA vertical POA error, +/- 2.9 MOA horizontal POA error

Another interesting finding was that although the Trijicon sight exhibited horizontal/vertical translation errors in POA, the total POA error for a given amount of eye movement seemed to be a little less than the total error for the same amount of eye movement for the EOTech and Holosun sights. This makes me wonder if the Trijicon engineers designed a reflective surface shape to minimize total error at the expense of some translation error, or if this just happens to be how the design of the Trijicon reflective surface shape works. It is an individual shooter decision as to whether the translation in POA error from horizontal to vertical and vice versa is acceptable in exchange for a slightly smaller total POA error.

Take aways:

Based on these test findings, the reported EOTech EXPS3 improvement in parallax induced POA error as compared to some of the best red dots is not accurate. The EOTech parallax induced POA error is about the same as a good reflex red dot sight. I suspect, but do not know, that the same may be true for some of the other EOTech sights because this is one of EOTech’s most recently released models so it would be surprising if the parallax induced POA error is worse than the earlier models.
It is important to state the obvious. The bottom line for practical use of all red dots is that centering the dot in the sight window during both zeroing and shooting longer distances is very important for accuracy.
When using a flip-down magnifier with either a holographic sight or a reflex red dot sight the window sight picture and FOV is greatly reduced, which naturally forces the shooter to keep the aiming dot more toward the center of the sight window, but it is still important to center the dot. It is also good practice to zero with the magnifier because any POA MOA shift due to the magnifier being on and off will produce a larger error measured in inches or cm at distance under magnification if the sight is zeroed without magnification as compared to the error in inches or cm at close range under 1X power if the sight is zeroed with magnification.
Even though the parallax errors are about the same, the EOTech EXPS3 and other EOTech models have the other advantages over reflex red dots. These advantages include a large FOV window and the same size aiming dot under magnification. While some red dots have similar FOV window sizes as compared to the large window EOTech models, the reflex sight aiming dots expand under magnification. Therefore, if the shooter is careful to keep the aiming dot in the center of the window the EOTech models can still be more accurate than a reflex red dot at long range under magnification due to the higher resolution of the aiming dot.
For me though, the main attraction was better parallax error and I'm not willing to trade the extra weight, size, cost and much lower battery life as compared to the excellent large window reflex red dots that are available for what amounts to a smaller, more precise aiming dot when using a flip-down magnifier. The EXPS3 I bought is going back to the seller.

Notes:
I have been using the Trijicon Patrol MRO for about 10 years and although the same model number is still a popular option that is readily available, optic manufacturers sometimes update designs without advertising the fact so newer Patrol MROs might have internal design updates that could change the parallax error performance, I don’t know about this. The EOTech EXPS3 is brand new and I picked up the Holosun 530-RD about 6 months ago, so these should be the latest designs.

Rio Precision Gunworks · Apr 14, 2024

Not shooting messenger, just a few points.

If you only tested one of each optic, you absolutely cannot make "bottom line" and "takeaway" statements with any kind of confidence whatsoever.

If your unit is taking substantial amount of shots with little or no cheek weld, I'd suggest better training and/or different equipment. If you're using raised optics, you should be using one of the many available printed cheek risers, or there are a handful of stocks with adjustable cheek. If you're taking shots from highly improvised positions, you should be training to use your visible or IR laser in these positions.

Burdy · Apr 14, 2024

You have found exactly the opposite of what has been tested numerous times, including the fact that the MRO is often cited as one of the worst in parallax. There are agencies who have dumped MROs for this exact reason after testing and gone to virtually anything else. With that being said, I'm not doubting your findings on your test, just know that's not the norm.

Also, you went through a lot to test this. The far easier (and more reliable) way is to mount up your EOTECH at the same height as your MRO on a continuous pic rail back to back and adjust the zeros until they are on top of each other. Put the dot on your target and when you move your head you will see the MRO separate from the EOTECH. You can swap their positions if you like, the end result should be the same. The EOTECH typically trounces the MRO in this test.

Milirad · Apr 15, 2024

Burdy said:
You have found exactly the opposite of what has been tested numerous times, including the fact that the MRO is often cited as one of the worst in parallax.

Thanks for the feedback. I understand that the results run counter to what has been long reported. That's why I was surprised/disappointed and also why I decided to take the time to take and report the test results. One of the first things I do when I check out any optic is informally test the parallax error and I expected the EOTech to be rock solid but it was immediately apparent that it was similar to reflex sights. Maybe I got a bad EOTech unit and a good MRO. The test procedure was quite simple and I repeated it several times for each optic because the results were different than the conventional wisdom, so I am confident in the general conclusion. The exact MOA of POA error for each optic could be off by as much as +/- 15% or so because it's pretty hard to read fractions of closely spaced gridlines at 7 yards on 1x. However, +/- 15% won't change the basic conclusion because the EOTech is supposed to be a fraction of the parallax sensitivity of the reflex sights, not 15% better. The particular EOTech unit I received was definitely in the same general ballpark for parallax error sensitivity with eye movement compared to the reflex sights.

I was planning to sell the MRO because it has noticeable parallax error sensitivity with eye position. After the testing described in the OP I realized the reason I notice it more on the MRO is because of the translation between horizontal/vertical eye movement and vertical/horizontal POA error. Parallax error is much more noticeable when you move your eye in one direction and the dot moves in a partially perpendicular direction to the eye movement. However, the MRO absolute parallax error (square root of horizontal error squared plus vertical error squared) is about the same as my other red dots and the EOTech I tested. I guess I will keep the MRO at least for now.

Because I had a bad experience with the EOTech I tried, I doubt I will go through the trouble of ordering another and re-testing to see if it was a bad unit. Maybe someone else can repeat the testing...

Milirad · Apr 15, 2024

Rio Precision Gunworks said:
If you only tested one of each optic, you absolutely cannot make "bottom line" and "takeaway" statements with any kind of confidence whatsoever.

Fair enough and thanks for the feedback. I thought about the "one-off" issue. Given that the EOTech is supposed to be over 80% less parallax error for a given amount of eye movement compared to reflex sights, it would be surprising if the larger than expected EOTech parallax error sensitivity in the measurements I made is a result of a one-off manufacturing tolerance problem, but it's possible. Also, if there were a batch of units that are many times the parallax error sensitivity the sight normally has, one would expect the EOTech QC processes to catch it.

Rio Precision Gunworks said:
If your unit is taking substantial amount of shots with little or no cheek weld, I'd suggest better training and/or different equipment. If you're using raised optics, you should be using one of the many available printed cheek risers, or there are a handful of stocks with adjustable cheek. If you're taking shots from highly improvised positions, you should be training to use your visible or IR laser in these positions.

The other day we practiced shooting from under a large object close to the ground and it was not possible to get a normal cheek weld unless you only wanted to shoot at ankles. Shooting in a tight area through a horizontal slit is another of many examples that don't allow for a normal weld and a riser doesn't make a difference. A laser would be ideal in some situations. I have been looking for one that has a max setting that is bright enough for reasonable CQ target distances in full daylight. Do you have any suggestions? A drawback with lasers of course is precise location signaling if there is any dust or fog.

Rio Precision Gunworks · Apr 15, 2024

Milirad said:
Fair enough and thanks for the feedback. I thought about the "one-off" issue. Given that the EOTech is supposed to be over 80% less parallax error for a given amount of eye movement compared to reflex sights, it would be surprising if the larger than expected EOTech parallax error sensitivity in the measurements I made is a result of a one-off manufacturing tolerance problem, but it's possible. Also, if there were a batch of units that are many times the parallax error sensitivity the sight normally has, one would expect the EOTech QC processes to catch it.

The other day we practiced shooting from under a large object close to the ground and it was not possible to get a normal cheek weld unless you only wanted to shoot at ankles. Shooting in a tight area through a horizontal slit is another of many examples that don't allow for a normal weld and a riser doesn't make a difference. A laser would be ideal in some situations. I have been looking for one that has a max setting that is bright enough for reasonable CQ target distances in full daylight. Do you have any suggestions? A drawback with lasers of course is precise location signaling if there is any dust or fog.

In the situations you describe, the parallax error isn't an issue. You're not going to take precision shots in those positions. Your shots will still be effective with the measurements you displayed in your first post.

As far as a laser, any of the popular full power lasers will accomplish what you want. If you're actually doing real CQB, you'll want to be running NVGs at some point. So a good illuminator/laser is required. If you're thinking more along home/self defense, thats different. However, you will won't be taking shots where that 3/4" matters.

If the $4k (or higher price) is too steep, then no offense, but you're not actually planning on needing to do real CQB work.

Almost no one ever picks an Eotech for CQB because of anything related to parallax. You seem to be not using realistic situations to make a decision on an optic based on a feature that isn't something professionals base their opinion on.

Rio Precision Gunworks · Apr 15, 2024

Milirad said:
Fair enough and thanks for the feedback. I thought about the "one-off" issue. Given that the EOTech is supposed to be over 80% less parallax error for a given amount of eye movement compared to reflex sights, it would be surprising if the larger than expected EOTech parallax error sensitivity in the measurements I made is a result of a one-off manufacturing tolerance problem, but it's possible. Also, if there were a batch of units that are many times the parallax error sensitivity the sight normally has, one would expect the EOTech QC processes to catch it.

The other day we practiced shooting from under a large object close to the ground and it was not possible to get a normal cheek weld unless you only wanted to shoot at ankles. Shooting in a tight area through a horizontal slit is another of many examples that don't allow for a normal weld and a riser doesn't make a difference. A laser would be ideal in some situations. I have been looking for one that has a max setting that is bright enough for reasonable CQ target distances in full daylight. Do you have any suggestions? A drawback with lasers of course is precise location signaling if there is any dust or fog.

Also, you’re giving yourself way too much credit in the one off thing. Like, an extraordinary amount of credit.

When almost every test or experience for literally years claims the exact opposite of your test…..

You need to start looking at what you likely did wrong or that you were unlucky enough to get a bad sample.

Not telling yourself that your test is showing X or Y is better or worse. The amount of bias that the opinion your test was valid is pretty extreme.

Anytime testing or research provides a result that is radically different from tests or accepted norms, it by default requires much more testing and data to back up.

If you are truly interested in the truth, I’d suggest you perform the test and other tests several times as well as have others contribute locally.

If the results remain unchanged, then get another unit, test and compare. Doing a one off test and basically concluding that everyone has been wrong and the manufacturer claims are not true, is the opposite of seeking the actual truth.

Convex · Apr 15, 2024

Not trying to shoot the messenger, but this is honestly what I think.

I think it's great folks ck out their gear to see if it's going to do what they bought it for, but that's different than testing your gear against some standard and then writing something in stone/making grand pronouncements about the gear, which can change the attitude of folks who might be considering buying gear which ultimately may affect these folks being able to "put food on the table" because of lost sales.

If something is wrong w/a piece of gear then so be it, maybe it doesn't sell, what's unfair is when it gets a "bad rap" it doesn't deserve, and/or the reverse when it's declared safe when it isn't which might cost somebody their life.

Absolutely everybody has the right to test out their gear, regardless of whatever you call a test, but whatever you come up with I would argue isn't something that can close to being considered as valid unless/until it's tested by folks who're professionally trained to test gear.

The video I've uploaded doesn't have any connection to an Eotech, but the video is an "eye opener" on how mistaken/wrong folks were about their tests which declared a gun to be "drop safe" that wasn't until it had some modifications that helped w/the problem of "inertia discharge".

sig sauer drop tests - Search Videos

www.bing.com

Testing out a theory, in a way which seems reasonable for me, is "Hey, I did A-B-C-D, this is how I did it", then let anybody who cares to put it under scrutiny/pick it apart, and see if your idea/theory "holds up" because even professionals at testing things forget things or leave something out, just ask the folks who put Hubble in orbit before they checked their math.

Milirad · Apr 15, 2024

I suspected there would be some doubt and suspicion on this post. I did the testing to satisfy my own curiosity. It was obvious right out of the box that the EOTech EXPS3 unit I received was anything but "parallax free" so I wanted to see how it compared to some of my red dots to decide if I would keep it. Before I posted the test results yesterday, I thought about not sharing the them to avoid getting hazed, but decided some Hide members cold find the information interesting and useful, so I decided taking some flak was worth it.

The point is not at all whether a CQC sight needs to be “parallax free”. A CQC sight (especially inside of 100 yards) absolutely, most certainly, and without question does not need to be parallax free and I never suggested this. Instead, the point is that some sights are widely perceived as being “almost parallax free” and “much less parallax than a red dot” and this perception influences buying decisions for Hide members and others, including me.

In addition, it's always a good idea to minimize equipment aiming error so more margin is provided to accommodate the shooter's skills and the situation (I need all the help I can get). Finally, for shooters who like to practice with and use their CQC rifles out to 200 or 300 yards, parallax error becomes more important.

To determine if the testing I did yesterday produced erroneous results, or if yesterday's results were an anomaly caused by a “one-off” bad EOTech unit, both of which have been suggested, I went to a local gun store and range this morning and worked with one of the sales team to do another side by side parallax induced error test. This time we took two new holographic sights out of their boxes, and performed a similar, a little simpler, parallax error test as compared to the one I did yesterday. I asked the store team member if he would allow me to use the two units in the shop and if he would make the same measurements I planned to make to see if he got the same results. The store had just opened so it was not busy at all and he was interested to see for himself what the parallax error is for a sight that is reported to be “parallax free”, so he said sure.

(continued in the post below)

Milirad · Apr 15, 2024

One sight, shown on the right in the picture below, is a second EOTech EXPS3. The other sight, shown on the left below, is a Vortex AMG UH-1 Gen II.

A group of black objects on a shelfDescription automatically generated

We placed the two sights side by side on a sturdy, stable half-wall. There is an indoor range that is 60 ft / 20 yards distance from the half wall. There are windows looking onto the range from the gun store. The windows are separated by 3.25 inch wide vertical window frames/dividers. We aimed both sights at the same window divider. We then moved our eye approximately +/- 0.5” across each of the sight windows while observing how far the aiming dot for each sight moved horizontally across the window divider. This was not a highly precise test, but it was sufficiently accurate to meet the goal of determining whether the EOTech parallax error measurements taken yesterday were “in the ballpark” as compared to a different EOTech EXPS3, or if the second unit we tested today would much better in parallax error. This test also allowed for a direct comparison of the Vortex sight parallax error to the EOTech sight error.

(continued in the post below)

Milirad · Apr 15, 2024

I tried to take a video of the aiming dot moving across the sight windows, but the dots become giant blotches that fill much of the window in an iPhone video, so it didn’t work.

Although we did not test vertical movement, which would have required a more involved aiming setup, we decided if the horizontal parallax error measured on the second EOTech unit today was much smaller than the error measured on the first unit yesterday, it would suggest yesterday’s result was an anomaly, or perhaps a one-off bad EOTech unit. On the other hand, if today’s horizontal parallax error testing of the second unit showed similar results to the parallax error measured on the first unit yesterday, then we could reasonably assume yesterday’s results were not a one-off and yesterday’s vertical parallax error testing of the first unit is likely a reasonable characterization of the EXPS3 vertical parallax error.

We both saw very close to the exact same amount of aiming dot movement in each of the sights. Here are the results:

When we moved our eye left and right about +/- 0.5”, the EOTech EXPS3 aiming dot moved about 3/4 of the width of the window divider, or about +/- 1.2”. Multiplying 3/4 x 3.25" / 2 = 1.2” by 100 yards divided by 20 yards = 1.2 x 5 = about 6 MOA.

When we moved our eye left and right about +/- 0.5”, the Vortex AMG UH-1 Gen II aiming dot moved about 1/3 of the width of the window divider. Multiplying 1/3 x 3.25 / 2 = 0.55” by 100 yards divided by 20 yards = 0.55 x 5 = 2.75 or about 3 MOA.

The results from today are consistent with the results from yesterday. The difference between today’s measured EOTech EXPS3 horizontal parallax induced error of 6 MOA and yesterday’s measured EOTech EXPS3 horizontal parallax induced error of 5 MOA is within measurement procedure tolerances for this kind of simple test. Yesterday’s testing was likely more accurate since it employed a grid target with closely spaced grid lines allowing for a more accurate observer estimate of the aiming dot movement. The unit I purchased and used in yesterday’s testing was from an online source. The unit we tested today was from a local store. It is possible that they both came from the same batch that had much larger parallax induced error than most EXPS3 sights.

My conclusion is that there are at least two EOTech EXPS3 units out there that have about the same parallax induced aiming error as a good red dot. The testing yesterday was definitely not a “one-off” result, and the cumulative test results are now at least a “two-off” result. This suggests it may be a “many-off” result.

A second conclusion is that there is at least one Vortex AMG UH-1 Gen II that has about half the parallax induced aiming error as compared to at least two EOTech EXPS3 units.

It would be great for another Hide member who has the time and some of the red dots to do a similar, perhaps more accurate, EOTech holographic red dot vs reflex red dot vs Vortex holographic red dot parallax error test.

Milirad · Apr 15, 2024

Finally, there has been so much testing of EOTech units in the past that I would bet confidently that there have been EOTech units that have much less parallax than an average reflex red dot. This is why I purchased one. In fact, the Vortex AMG UH-1 Gen II has about half the parallax error of the reflex red dots I tested, so I'm sure holographic sights can be better than reflex sights. However, better than reflex sight parallax error is not the case in the two EOTech units I tested. I suppose the question is whether the basic design is different in the new EXPS3 as compared to other EOTech units tested in the past, or if there is a bad batch of units moving through the distribution channels.

Convex · Apr 16, 2024

I don't think anyone has showed up until now who hasn't given you the highest civility, courtesy, and respect. I don't think you've been hazed or hassled, folks simply have expressed a caution and healthy doubt about your method, and w/o getting personal.

Again, I'm just telling you what I think and I may be wrong about what I think, but I am entitled to say what I think as you are, and this discussion up to this point has been pretty amicable, which can happen even when folks disagree w/you.

My issue w/what's been said is reflected by this statement....

"This was not a highly precise test, but it was sufficiently accurate to meet the goal of determining whether the EOTech parallax error measurements taken yesterday were “in the ballpark” as compared to a different EOTech EXPS3, or if the second unit we tested today would much better in parallax error."......

The best professionals who're trained to test things will conduct tests on many samples testing them with precision equipment, with the requirement that the test is as precise as possible.

I'm sorry, but for me the phrases

"This was not a highly precise test" --------"but it was sufficiently accurate------"in the ballpark"

Don't work for me because these optics were put together w/precision and their performance should be questioned w/precision and w/precision equipment when it comes to drawing valid conclusions for anyone but yourself.

I'm not trying to attack or haze you, I just simply disagree w/what you've said.

The "gentle souls" around here who will come at you like "freight train" have not showed up... yet.

Milirad · Apr 16, 2024

You are right, I'm just an end user when it comes to shooting sports, not a professional tester of optics. As such I understand and respect your point of view and don't blame you for discounting my reported results. All I can say in response is I agree that it is very hard to get exact measurements for this kind of error, but it's not hard at all to move your eye back and forth a little with several red dot sights, including two samples of the model that seems to be in controversy, and record how much the aiming dots move. It's not rocket science and is very similar to the way an end user uses the tool. Even without a more rigorous test, if a shooter moves his/her head half an inch and the POA shifts "about 5 MOA", it is what it is. In my view the point is, whether the dot moves 4 MOA, 5 MOA or 6 MOA, the movement is in reflex sight territory, not way better as I and many others would expect.

If it is necessary to make the results more credible, maybe I will carve out the time to design and execute a more rigorous test and figure out how to video the results. I suspect that a closer target with camera optics that have high f-stop with high depth of field might do the trick.

Also, the EXPS3 is an amazing sight. The window is huge and the feature where the center dot MOA target coverage doesn't grow under magnification is very advantageous for longer range performance. Parallax error also isn't a show stopper even for shots that demand high accuracy, provided that the shooter knows to keep the dot close to the center of the window and in the same location that was used for zeroing, just like a reflex sight. I'm not out to bash any products, just share what I learn now and then when it's something I can't find much information on.

Convex · Apr 16, 2024

Disagree w/you yes

Discount your "sweat equity"

No.

In fact my compliments.

Cutout · Apr 16, 2024

Pardon my ignorance, and I mean that sincerely, but isn't 7 yards too close to test parallax on a red dot or holographic? I thought they were supposed to be somewhat parallax free at a certain distance, such as 50 feet (depending on the optic). I would be interested to see if you could reproduce the same parallax error at 100 yards, or even at 50 yards. If so, I would really like to know when/if an EOTech starts to surpass red dots in being parallax "free."

Rio Precision Gunworks · Apr 16, 2024

You can't have it both ways. You can't post a "test" and give statements of results such as you did.....but also say that you're just an end user and not a professional tester. As you wouldn't be claiming that if people didn't disagree with you. You also can't claim to be the "messenger" as you're not a messenger at all. You're the source of the information itself.

You've made a definitive statement that "Contrary to widely held belief, the EOTech EXPS3 holographic sight has about the same parallax induced POA error as compared to reflex red dots Trijicon Patrol MRO and Holosun 530-RD, which was surprising to learn."

Which is based on a single sample size with a test that was done with optics placed on a wall and your eye moved "approximately."

I applaud the time you took to do this, but you essentially wasted your time. This just isn't how you go about testing things like this. This is also why all professional level testing has historically shown the exact opposite of your testing. Again, you're giving yourself far too much credit on your observations off a wall and a tape measure.

Feel free to not use an optic based on your personal observations. But to present this as valid data with definitive statements is doing a disservice to anyone who reads this and takes it at face value.

Rio Precision Gunworks · Apr 16, 2024

It's also a fairly moot point for CQB type scenarios anyway. You already have a varying amount of hold offs needed for height over bore, and you're not going to be able to judge distance in high stress/speed situation enough that you'd be precise enough with your vertical hold offs that your horizontal parallax is going to make much of a difference.

Let's say your testing and data is valid. You have basically painted yourself into a corner that the following situation has to happen for that data to be useful:

- You have a precision shot where parallax matters
- You are unable to maintain a proper cheek weld due to some sort of improvised position
- You are unable to reposition to make the precision shot
- You are unable to position your head in a way that brings the reticle closer to center
- There is no one else there to make the shot from a better position

The second that you change any of those variables, and it doesn't matter again. And its pretty hard to think of a situation were you wouldn't be able to float your head enough to get the reticle back into the center of the FOV to be close enough that your height over bore hold off is as large or larger variable in shot placement.

This is why almost no once cites parallax when they are choosing or not choosing an eotech. The factors that are much more important are the FOV, battery, controls, reticle....etc.

Milirad · Apr 16, 2024

Cutout said:
Pardon my ignorance, and I mean that sincerely, but isn't 7 yards too close to test parallax on a red dot or holographic? I thought they were supposed to be somewhat parallax free at a certain distance, such as 50 feet (depending on the optic). I would be interested to see if you could reproduce the same parallax error at 100 yards, or even at 50 yards. If so, I would really like to know when/if an EOTech starts to surpass red dots in being parallax "free."

That's an good question and I don't know. I am very familiar with parallax free distance for scopes that don't have parallax adjustment but I was not aware that this might be an issue with red dots, specifically holo sights, as well. Will look into it tonight. Thanks!

Milirad · Apr 16, 2024

I did not find anything concrete and reliable on parallax free distance for holographic or reflex red dots. Knowing the way these sights work, project a dot at a certain point of aim angle on a carefully designed curved reflective surface, I would not expect there to be a particular distance that would have different parallax error for a specific dot location in the sight window as compared to any other distance.

While researching Cutout's interesting question, I ran across this EOTech webpage:

https://www.eotechinc.com/faq

Scrolling down to this question:
DOES THE HWS HAVE PARALLAX?
I found the following official EOTech statement about the parallax induced error in their holographic weapon sights (HWS):

"All optics experience varying degrees of parallax depending on use and operating conditions. Parallax is an apparent change in the point of aim resulting from a change in the position of the shooter. EOTECH’s sights have little parallax when the reticle is in the center of the viewing window, which is the optimum sighting position and also is the correct place for zeroing the sight. On the other hand, if the user is looking through the sight at the outer edge of the sight window – an off-axis view – the parallax error might be up to 4±3 MOA (or a total of 14 MOA across the viewing window) at 71˚ F (for a sight properly zeroed). In other words, parallax can increase as the user’s view approaches the edge of the EOTECH viewing window. To put this possible amount of off-axis error into perspective, 7 MOA equates to 1.75 inches at 25 yards or 7 inches at 100 yards. Viewing through the center of the window achieves the least parallax error. Parallax may increase as temperature changes from 71˚ F. At operating temperature extremes of -40˚ F or 122˚ F, there may be an additional 4 MOA of parallax."

All of the recorded EXPS measurements in this post are in the middle of the range EOTech says users should expect. The measured results are less than the max error EOTech says to expect because instead of moving the dot all the way to the edges of the window, which seems unrealistic in a real shooting scenario, the test procedure limited eye movement to +/- 0.5" horizontal and +/- 0.35" vertical, which moved the dot over about ⅔ of the sight window. This seems like a more realistic expectation in a field scenario rather than expecting the shooter to use the red dot all the way at the edges of the window. Overall, the EXPS3 measured results are entirely consistent with what EOTech says to expect. Not too bad for a simple set of tests.

My apologies for not finding this sooner - it would have saved readers, and me, some time. It is nice that EOTech is so straightforward and honest about their products, makes me like the brand more than I already did.

Now that this post includes an official EOTech statement about what kind of parallax error to expect in their holo sights along with some measurement results that are consistent with what EOTech says, and some measurement results that show the Vortex holo sight also exhibits meaningful parallax error (albeit less), we can confirm that the widely reported statements that holographic sights are "almost parallax free" are simply untrue. Some holo sights are better than red dots, but not any where near parallax free, and other holo sights are about the same as red dots.

Cutout · Apr 16, 2024

I haven't done a lot of research on this, so I haven't found an official number (I am admittedly not an expert on red dots or HWS sights). What I have found is a lot of statements on forums to the effect of "most red dots are ~25 feet to minimum parallax and 50 feet to being practically parallax free." So I am not sure about the actual physics of it, but it does appear that parallax error at closer distances may not be proportional to parallax at further distances. I would love to hear someone weigh in on this that knows more than me on the matter (wouldn't take much).

Convex · Apr 16, 2024

Wait a minute.

I believe you stated this...

"Contrary to widely held belief, the EOTech EXPS3 holographic sight has about the same parallax induced POA error as compared to reflex red dots Trijicon Patrol MRO and Holosun 530-RD, which was surprising to learn."....

What does "Contrary to widely held belief" mean. Saying that is meaningless until you give us specifics.

Then this..

"Now that this post includes an official EOTech statement about what kind of parallax error to expect in their holo sights along with some measurement results that are consistent with what EOTech says, and some measurement results that show the Vortex holo sight also exhibits meaningful parallax error (albeit less), we can confirm that the widely reported statements that holographic sights are "almost parallax free" are simply untrue."......

"widely reported statements" from who/where.

W/o specifics you're being the judge of what you want us to know instead of providing us w/specifics so we can judge for ourselves.

What Eotech said above includes...

"the parallax error might be up to 4±3 MOA

In other words, parallax can increase as the user’s view approaches the edge of the EOTECH viewing window.

Parallax may increase as temperature changes from 71˚ F. At operating temperature extremes of -40˚ F or 122˚ F, there may be an additional 4 MOA of parallax."

I've had Eotech for years, and I've talked to them on the phone, this is something they might tell you over the phone in a general discussion.

Eotech is making a general statement and they're not saying anything definitive, they're not spouting/documenting rigorous test results, so what they say isn't a validation of your "tests" or how you did them.

I'm done.

Good luck.

Milirad · Apr 17, 2024

Cutout said:
I haven't done a lot of research on this, so I haven't found an official number (I am admittedly not an expert on red dots or HWS sights). What I have found is a lot of statements on forums to the effect of "most red dots are ~25 feet to minimum parallax and 50 feet to being practically parallax free." So I am not sure about the actual physics of it, but it does appear that parallax error at closer distances may not be proportional to parallax at further distances. I would love to hear someone weigh in on this that knows more than me on the matter (wouldn't take much).

OK - I will do some additional testing when I get a chance to see if there is variation in the MOA error as a function of distance. I have 6 different red dot models I can try at different distances and can go back to the gun shop to try the EOTech and Vortex models at different distances. I won't measure the exact parallax error because the question is whether or not there is a "parallax free distance" so the MOA error is either going to get small at some distance or not and that is easier to test than the exact MOA error numbers at lots of distances (which I expect not to change much if any).

For what it's worth, the second set of tests in the gun shop were done at 60' so if the sights are supposed to be parallax tree at about 50 feet that was close to 50', and the EOTech results were not any better than the first tests at 21'. I doubt there is a truly parallax free distance for any red dot like there is for lots and lots of scopes.

Cutout · Apr 17, 2024

Milirad said:
OK - I will do some additional testing when I get a chance to see if there is variation in the MOA error as a function of distance. I have 6 different red dot models I can try at different distances and can go back to the gun shop to try the EOTech and Vortex models at different distances. I won't measure the exact parallax error because the question is whether or not there is a "parallax free distance" so the MOA error is either going to get small at some distance or not and that is easier to test than the exact MOA error numbers at lots of distances (which I expect not to change much if any).

For what it's worth, the second set of tests in the gun shop were done at 60' so if the sights are supposed to be parallax tree at about 50 feet that was close to 50', and the EOTech results were not any better than the first tests at 21'. I doubt there is a truly parallax free distance for any red dot like there is for lots and lots of scopes.

I appreciate your testing of this and I'll be really interested to hear your results.

Milirad · Apr 17, 2024

Convex said:
Wait a minute.

I believe you stated this...

"Contrary to widely held belief, the EOTech EXPS3 holographic sight has about the same parallax induced POA error as compared to reflex red dots Trijicon Patrol MRO and Holosun 530-RD, which was surprising to learn."....

What does "Contrary to widely held belief" mean. Saying that is meaningless until you give us specifics.

Then this..

"Now that this post includes an official EOTech statement about what kind of parallax error to expect in their holo sights along with some measurement results that are consistent with what EOTech says, and some measurement results that show the Vortex holo sight also exhibits meaningful parallax error (albeit less), we can confirm that the widely reported statements that holographic sights are "almost parallax free" are simply untrue."......

"widely reported statements" from who/where.

W/o specifics you're being the judge of what you want us to know instead of providing us w/specifics so we can judge for ourselves.

What Eotech said above includes...

"the parallax error might be up to 4±3 MOA

In other words, parallax can increase as the user’s view approaches the edge of the EOTECH viewing window.

Parallax may increase as temperature changes from 71˚ F. At operating temperature extremes of -40˚ F or 122˚ F, there may be an additional 4 MOA of parallax."

I've had Eotech for years, and I've talked to them on the phone, this is something they might tell you over the phone in a general discussion.

Eotech is making a general statement and they're not saying anything definitive, they're not spouting/documenting rigorous test results, so what they say isn't a validation of your "tests" or how you did them.

I'm done.

Good luck.

I respect your diligence with respect to the theoretical doors that may be left open here. I have worked in the technical fields all my adult life and have conducted many hundreds of tests and experiments on all sorts of products. It is very hard to close every door regarding what the performance of a product might or might not be in all possible circumstances. We therefore usually design tests that represent real world performance to the greatest degree possible and then make enough measurements to form conclusions that are likely to be correct, but not guaranteed to be correct in all circumstances. That is often the alternative to never making any conclusions. In this case, the red dots tested for this post most definitely moved as have been described with the eye movements that have been described and the results are entirely consistent with the EOTech statement. In my world that is pretty conclusive. It might be that there are other holographic sights out there somewhere that would be much better in parallax error, not the ones tested for this post though.

Convex · Apr 17, 2024

Milirad said:
In this case, the red dots tested for this post most definitely moved as have been described with the eye movements that have been described and the results are entirely consistent with the EOTech statement. In my world that is pretty conclusive.

I just got home and saw this, so I guess I'm jumping back in for a bit.

You were asked specifics about your premise, which you brought up.

I'll ask you again, what does "Contrary to widely held belief" mean, who?

Again; your comment about "widely reported statements" are from who/where.

In my world, you make statements/you bring something up, you respond by explaining what you meant, and preferably by giving specifics instead of ignoring/generalizing.

You "tested" 2 samples, that isn't conclusive of anything and the Eotech statement isn't suggesting the same thing you were saying. Everything in their statement was "maybe" and yours wasn't.

You said this...

"The test procedure for each sight was to center the dot in the middle of the window while aiming it at a grid target with close grid spacing, then move my eye side to side by the same distance for each sight (+/- 0.5”) and up and down by the same distance for each sight (+/- 0.35”) and then record the dot movement in inches on the grid. The target was set up at 7 yards which was far enough away to get enough dot movement for a reasonably accurate estimation of POA shift on the grid.....

You're conducting a "test" based on your premise, and you're also the participant in your own test, you both observer and participant-guinea pig and observer, all wrapped into one, you haven't conducted enough "tests" (w/different participants) to pay any "lip service" to repeatability;

w/these two red dots or any others.

really?

When you talked about moving your eyes, how did you measure that, you don't bother to tell us. Have you had your vision tested. You don't say. You don't clue us in on anything on something you've done once or twice, you don't repeat the test w/other participants but say all this is pretty conclusive.

Somebody else mentioned you trying to have it both ways...

#14 You say this...

"You are right, I'm just an end user when it comes to shooting sports, not a professional tester of optics."

Which then "morphs" into this...

"We therefore usually design tests that represent real world performance to the greatest degree possible and then make enough measurements to form conclusions that are likely to be correct, but not guaranteed to be correct in all circumstances."

Which is it.

Can't be both.

"Test" all you want, but when you suggest that what you did should be considered as "pretty conclusive", as far as I'm concerned you haven't come close to doing that.

In school they never let me score my own tests, that also works when you conduct a test.

Cutout · Apr 17, 2024

Convex said:
I'll ask you again, what does, "Contrary to widely held belief" mean, who?

Again; your comment about "widely reported statements" are from who/where.

For what it's worth, I've always heard that EOTechs are parallax free or at least more parallax free than other optics, due to them being HWSs instead of red dots. So I can't speak to how "widely held" that belief is, just to my personal experience which is that I've heard it repeated for the last 20 years of being into this stuff, be it through forums, videos, comment sections, gun counter talk, etc. In the old ARFCOM forum days, a common discussion was EOTech vs Aimpoint (there weren't as many options for duty grade red dots at the time), and this was usually considered a point in the EOTech's favor. It has been such an uncontested "fact" for so long that I am still skeptical of the results of this test. I am not an expert on the subject of red dots or HWSs, but I do agree that this is a common belief that is repeated.

Convex · Apr 17, 2024

What Eotech said about about parallax is what I paid attention to when I bought my Eotech 7 or 8 years ago. and the internet is rife w/bogus shit.

My attitude is reflected by what most of the other folks on here said about the Eotech.

Milirad · Apr 17, 2024

Convex said:
I'll ask you again, what does "Contrary to widely held belief" mean, who?

A couple of many examples are provided below.

(1) From: https://tacticalgear.com/experts/reflex-sights-vs-holographic-sights-which-do-you-need
"Reflex sights offer good eye relief and low parallax, but holographic sights are even better in both respects... "

(2) From: https://www.gunbuilders.com/blog/holographic-vs-red-dot-sights-which-to-pick/
"Holographic sights have no parallax error. That means no matter where your eye is located behind the reticle, the position of the reticle (point of aim) relative to the target remains the same at all times. Can't get a good cheek weld on your buttstock? Aiming from the prone instead of standing? A poor sight picture won't matter. Your shots will land exactly where the reticle is pointing."

Convex said:
Again; your comment about "widely reported statements" are from who/where.

See above and many other examples.

Convex said:
In my world, you make statements/you bring something up, you respond by explaining what you meant, and preferably by giving specifics instead of ignoring/generalizing.

You "tested" 2 samples, that isn't conclusive of anything and the Eotech statement isn't suggesting the same thing you were saying. Everything in their statement was "maybe" and yours wasn't.

You said this...

"The test procedure for each sight was to center the dot in the middle of the window while aiming it at a grid target with close grid spacing, then move my eye side to side by the same distance for each sight (+/- 0.5”) and up and down by the same distance for each sight (+/- 0.35”) and then record the dot movement in inches on the grid. The target was set up at 7 yards which was far enough away to get enough dot movement for a reasonably accurate estimation of POA shift on the grid.....

You're conducting a "test" based on your premise, and you're also the participant in your own test, you both observer and participant-guinea pig and observer, all wrapped into one, you haven't conducted enough "tests" (w/different participants) to pay any "lip service" to repeatability;

Sorry, I can't tell what you are getting at here. The test was to move the eye around like a shooter would and see how far the dot moved and convert that to MOA. It's simple, practical and real world.

Convex said:
w/these two red dots or any others.

really?

When you talked about moving your eyes, how did you measure that, you don't bother to tell us. Have you had your vision tested. You don't say. You don't clue us in on anything on something you've done once or twice, you don't repeat the test w/other participants but say all this is pretty conclusive.

Good question. In the first test, for the horizontal direction three lines were drawn directly below where the eye was positioned: one line on the centerline of the sight, and two lines at +/- 0.5" from the center line of the sight and the eye was moved back and forth until it was directly over the two outside lines, and the +/- dot travel on the grid target was recorded. For the vertical direction masking tape was used between two stacks of books just in front of the eye position so that the red dot sights were blocked from view at +/- 0.35" from the center of the sight. Of course there was not nearly as much time to set up a test in the gun shop, so we did our best to limit horizontal travel to about +/- 0.5" because the goal was to see if the previous, more accurate tests produced results that would not be repeated with a second EOTech unit, or were about right. It turned out the first days testing was about right. It also turned out that the Vortex unit had half the horizontal parallax error sensitivity as the EOTech sight. I would trust the first day test results more than the second because it was more carefully set up with hard limits on eye travel and a closely spaced grid target for measuring aiming dot travel.

Convex said:
Somebody else mentioned you trying to have it both ways...

#14 You say this...

"You are right, I'm just an end user when it comes to shooting sports, not a professional tester of optics."

Which then "morphs" into this...

"We therefore usually design tests that represent real world performance to the greatest degree possible and then make enough measurements to form conclusions that are likely to be correct, but not guaranteed to be correct in all circumstances."

Which is it.

I am a user of red dot sights and I have tested many products. I am not a professional tester of red dots or other optics. I have a great deal of product test experience in multiple technical fields. These are all completely consistent facts.

Convex said:
Can't be both.

"Test" all you want, but when you suggest that what you did should be considered as "pretty conclusive", as far as I'm concerned you haven't come close to doing that.

In school they never let me score my own tests, that also works when you conduct a test.

I don't feel anything needs to be clarified or restated in my reported information in this post. I posted it for the benefit of other hide members. I feel the results speak for themselves, especially in light of the EOTech statements about parallax error in their products. Every reader can read and interpret the results for themselves. My interpretation is that both of the EOTech sights I tested were in the same "ballpark" for parallax error sensitivity as the reflex sights I tested and the Vortex was about half the parallax error sensitivity of the EOTechs and reflex sights. Neither of the holographic sights were any where near an order of magnitude better in parallax error sensitivity as compared to than the reflex sights, although the Vortex was roughly half the sensitivity which is a very meaningful improvement.

Milirad · Apr 17, 2024

Convex said:
What Eotech said about about parallax is what I paid attention to when I bought my Eotech 7 or 8 years ago. and the internet is rife w/bogus shit.

The above statement is very different than saying there isn't a bunch of information out there saying holographic sights are way better in parallax error than a reflex red dot. The above statement I agree with and that is why I posted the test results.

Convex · Apr 18, 2024

So what. Why would it need to be said differently. The point is your "test results" weren't going to change what folks around here already knew.

What has been said about you is true, you give yourself too much credit.

Milirad · Apr 18, 2024

Perhaps not everyone knows what you know. And if you already knew the results, why give me such a hard time for posting them?

Convex · Apr 18, 2024

LOL

I treated you w/kid gloves...

Like I told you before, the folks who're going to give you a hard time haven't shown up yet.

Milirad · Apr 18, 2024

Ok, guess I just don’t understand. Take care.

Convex · Apr 18, 2024

Hang around for awhile

you will....

Makinchips208 · Apr 18, 2024

The howlers are coming! lol.
Hats off to the effort you put in!

Red dots do have parallax. Some more some less. Does it matter? Not usually very much considering the application.

Burdy · Apr 18, 2024

Milirad said:
Perhaps not everyone knows what you know. And if you already knew the results, why give me such a hard time for posting them?

Actually, there are people here who know more on this subject and have tried to gently nudge you that you are incorrect in your testing/assessment. Unfortunately sometimes those that know more and that could easily dispel your testing methods and results, simply can't, because in doing so would violate NDAs and other proprietary information. All they can say is, this has been tested, repeatedly, at the highest levels, under extreme scrutiny with state of the art technology and methodology and the results are contrary to yours.

You seem like a good dude with good intentions and are taking flak for trying to help the community with your findings which I can appreciate but it's tough watching you continue to spin your wheels in the mud.

There is really nothing more I can say.

Macht · Apr 18, 2024

Burdy said:
Actually, there are people here who know more on this subject and have tried to gently nudge you that you are incorrect in your testing/assessment. Unfortunately sometimes those that know more and that could easily dispel your testing methods and results, simply can't, because in doing so would violate NDAs and other proprietary information. All they can say is, this has been tested, repeatedly, at the highest levels, under extreme scrutiny with state of the art technology and methodology and the results are contrary to yours.

You seem like a good dude with good intentions and are taking flak for trying to help the community with your findings which I can appreciate but it's tough watching you continue to spin your wheels in the mud.

There is really nothing more I can say.

And yet the statement from the manufacturer lines up with the test results and also contradicts the conventional internet dogma...

Milirad · Apr 18, 2024

This is an interesting statement:

"...people here who know more on this subject and have tried to gently nudge you that you are incorrect in your testing/assessment.... Unfortunately sometimes those that know more and that could easily dispel your testing methods and results, simply can't, because in doing so would violate NDAs and other proprietary information."

It seems to suggest that one needs to have secret sauce information on to make some holographic sights work with very low parallax error. I wonder what is in that secret sauce?

Not having the secret sauce is a tricky prospect for many users who are not in the know, and for the EOTech people who wrote up the company's statement on what a user should expect for parallax error, all of whom don't seem to have the secret sauce because they characterize their experience with EOTech parallax induced aiming error in a way that is consistent with EOTechs statement and the tests posted here.

All joking aside, one of the the only things I can think of, grasping at straws, is perhaps there is a small area in the middle of the window where the dot has much less parallax as long as it doesn't go outside of the small area. However, this is just keeping the dot in the middle which is what a shooter would do when the shooter knows there is parallax error when the eye does not center the dot in the window. Another possibility might be the shooter learns through training what the MOA aiming error is at different dot locations in the window, so the shooter can use hold off to correct for the error.

Cutout · Apr 18, 2024

I’m confused. Are the folks who haven’t shown up yet and have the secret sauce (the ones we’re taking offense on behalf of) going to agree that EOTechs have parallax error similar to the statement that EOTech made on their website, or are they going to disagree?

1911hombre · Apr 18, 2024

Burdy said:
tough watching you continue to spin your wheels in the mud.

EL OH EL.

Convex · Apr 19, 2024

Macht said:
And yet the statement from the manufacturer lines up with the test results and also contradicts the conventional internet dogma...

The statement "this wasn't a highly precise test" is wrong, a test that isn't precise isn't a test.

The biggest mistake somebody can make is to believe that a so called "test" involving a "one off" or "two off" sampling process proves/contradicts anything, because the results are/seem to be the same, which is why the process of validating something involves repeatability.

Repeatability involving as many tests as possible w/as many samples as possible with different participants/observers.

How about a "thought experiment" relating to this discussion and the value of repeatability.

Let's make it simple/about flipping coins, two pennies, any two pennies.

Let's say part of the test is for two people to stand 5 feet away from each other as they each take a penny and flip it up at least 5 or 6 feet in the air, letting the pennies hit the ground or a hard floor, and record which coin came up heads or tails, and of course let's do it twice.

So they both flip their pennies once, both pennies come up heads.
They both flip their pennies a second time, and again both coins come up heads.

The guy who is trying to prove his theory by conducting this test tells everybody stop, "that's enough, I think I've proved what I wanted to prove."

Somebody asks the guy "what were you trying to prove"; his answer is....

"When these two guys stand here and flip their 2 pennies like this, they'll both come up heads every time."

I made it pennies because anybody who isn't in a coma will know how wrong this guy is except him.

Macht · Apr 19, 2024

Convex said:
The statement "this wasn't a highly precise test" is wrong, a test that isn't precise isn't a test.

The biggest mistake somebody can make is to believe that a so called "test" involving a "one off" or "two off" sampling process proves/contradicts anything, because the results are/seem to be the same, which is why the process of validating something involves repeatability.

Repeatability involving as many tests as possible w/as many samples as possible with different participants/observers as possible.

How about a "thought experiment" relating to this discussion and the value of repeatability.

Let's make it simple/about flipping coins, two pennies, any two pennies.

Let's say part of the test is for two people to stand 5 feet away from each other as they each take a penny and flip it up at least 5 or 6 feet in the air, letting the pennies hit the ground or a hard floor, and record which coin came up heads or tails, and of course let's do it twice.

So they both flip their pennies once, both pennies come up heads.
They both flip their pennies a second time, and again both coins come up heads.

The guy who is trying to prove his theory by conducting this test tells everybody stop, "that's enough, I think I've proved what I wanted to prove."

Somebody asks the guy "what were you trying to prove"; his answer is....

When these two guys stand here and flip their 2 pennies like this, they'll both come up "heads" every time.

I made it pennies because anybody who isn't in a coma will how wrong the guy is except him.

I have no idea what point you have been trying to make in this entire thread. Nothing you've said has added value in any way.

Are you suggesting that Eotech is incorrect about their product specification? Or are you suggesting serious errors exist with the original poster's testing methodology outside of sample size?

I would assume such a learned individual would understand the significance of two independent samples falling out of specification? That is, if the common statement of "zero parallax error" were in fact true, finding one sample that deviated from that behavior is noteworthy and two samples is significant. To put numbers to an example: if you were to assume that Eotech had a six sigma capable process (unlikely) the odds of finding a single defective product would be 3.4/1,000,000 or 1/3,400,000. The odds of finding two defective products would then be 1/11,560,000,000,000. Given those astronomical odds, three alternate explanations are more likely: one, the actual process capability is poorer than expected, two, the samples are not defective and are actually representative of the average product, or three, the testing methodology is flawed.

Obviously two samples is not definitive, but two samples deviating from expected behavior is meaningful. In this case, it turns out that the samples aren't deviating from expected behavior as stated by the manufacturer, but the original test isn't nearly as flawed as you're trying to portray.

Makinchips208 · Apr 19, 2024

Convex said:
The statement "this wasn't a highly precise test" is wrong, a test that isn't precise isn't a test.

The biggest mistake somebody can make is to believe that a so called "test" involving a "one off" or "two off" sampling process proves/contradicts anything, because the results are/seem to be the same, which is why the process of validating something involves repeatability.

Repeatability involving as many tests as possible w/as many samples as possible with different participants/observers.

How about a "thought experiment" relating to this discussion and the value of repeatability.

Let's make it simple/about flipping coins, two pennies, any two pennies.

Let's say part of the test is for two people to stand 5 feet away from each other as they each take a penny and flip it up at least 5 or 6 feet in the air, letting the pennies hit the ground or a hard floor, and record which coin came up heads or tails, and of course let's do it twice.

So they both flip their pennies once, both pennies come up heads.
They both flip their pennies a second time, and again both coins come up heads.

The guy who is trying to prove his theory by conducting this test tells everybody stop, "that's enough, I think I've proved what I wanted to prove."

Somebody asks the guy "what were you trying to prove"; his answer is....

"When these two guys stand here and flip their 2 pennies like this, they'll both come up heads every time."

I made it pennies because anybody who isn't in a coma will know how wrong this guy is except him.

“an off-axis view – the parallax error might be up to 4±3 MOA (or a total of 14 MOA across the viewing window) at 71˚ F (for a sight properly zeroed).” From eotech website.

And a test is simply a test. A test of one product is still a test.

And finally, This kind of reminds me of theorems and proofs in math and geometry. And where someone like @Aftermath could really correct me.

koshkin · Apr 19, 2024

I have to apologize that I did not read the whole thing. I will add a couple of points that, perhaps, have been considered.

1) Most holographics and red dot sights are designed to have minimal parallax in the 40 to 50 yard range. Measured angular parallax will be higher closer than that and further than that.

2) With well designed holographics and red dots, there is a center sweetspot where parallax is very low. As you get closer to the edges it goes up.

ILya

Convex · Apr 20, 2024

Then you don't know how to read which is why you have no idea.

As to the "learned individual" sarcasm/troll, just plain fuck you on that.

The "coin flip" example didn't mention him, and it wasn't aimed at him, only at an idea and my opinion of the logic being used here and it's "on the money", you injected this fucking troll connecting me to him and making this personal, which was unnecessary.

I quoted you and came up w/the "coin flips" I don't care whether you like it or not, it's what I had to say.

Don't put words in my mouth, I didn't suggest a thing about Eotech being incorrect; they're talking in general terms w//a bunch of "can" and "maybe", and what he says he did in his test was not what Eotech said.

You yourself said two samples isn't enough, that's the point. He said out of his own mouth that it wasn't a highly precise test so what are you talking about. What he's said about his test is what I've said about this test.

Your rant below the 1st couple of sentences is utter nonsense. You can't understand the example of the coin flips, then you don't want to understand.

This is also nonsense... "but two samples deviating from expected behavior is meaningful."

"expected ?" You use blinds and double blinds to "wean out" expecting a certain result. which is how you eliminate bias. The example of the "coin flips" shows how wrong just relying on 2 samples can be.

There is no deviation because there were only two samples.

The first thing a troll does is to pretend to not understand, If you don't understand that then this is just you trolling, you asshole.

Milirad · Apr 20, 2024

koshkin said:
I have to apologize that I did not read the whole thing. I will add a couple of points that, perhaps, have been considered.

1) Most holographics and red dot sights are designed to have minimal parallax in the 40 to 50 yard range. Measured angular parallax will be higher closer than that and further than that.

2) With well designed holographics and red dots, there is a center sweetspot where parallax is very low. As you get closer to the edges it goes up.

ILya

Thanks Ilya. I was wondering if you might see this and weigh in. As always your experience and knowledge are greatly appreciated.

I was wondering about whether the parallax error sensitivity due to to a given amount of eye displacement distance might be better in the center of a holo (or reflex) sight window might be considerably better than further toward the window edges. This makes intuitive sense. When shooting short distances parallax error is less of an issue so it can be ok to allow the dot to be away from center. For more careful long shots a shooter would normally take more care to center the dot in the window, but there is no marking to confirm the dot is centered so the dot will generally not be at the perfect center no matter how careful the shooter is (unless there is a co-witnesses with iron sights at the center of the window which is generally distracting for the CQB sight picture). Given that the shooter has no way to confirm the dot is perfectly centered for longer more careful shots, even though the parallax error away from the center of the window might be about the same, if the parallax error sensitivity is considerably less for holo sights close to the center of the window as compared to parallax error sensitivity for reflex sights this would still be a substantial advantage for holo sights.

At some point it would be nice to understand how a reflective curved surface projects and aim point that has a specific distance at which there is less parallax. At first blush it would seem that the eye movement would result in changes in the orientation of an infinite aim point line in 3-D space, originating at the front/target end of the sight window, that would not be sensitive to the axial distance along the line to the target, but given what you stated I'm sure there is something I'm missing on this.

Question for you: As I have been thinking about this topic it occurred to me that the eye relief distance to the sight could have a meaningful impact on parallax error. There could well be an eye relief distance where the POA sight lines from the rear of the curved reflective surface intersect, which might minimize the parallax error. Also, in separate potential effect, for a given fixed eye movement distance the angular movement of the eye with respect to the sight window center decreases as the eye relief distance increases. This may suggest that longer eye relief reduces parallax error sensitivity for a given fixed eye movement distance, albeit at the expense of FOV within the window. Is there an eye relief distance where parallax error is minimized, or is parallax error is insensitive to eye relief distance?

For educational purposes, and just out of curiosity, I will see if I can get my hands again on a couple holo sights and do two or three additional tests vs reflex red dots.

(1) To see how much better a typical holo is in the center of the window rather than over the full window, the eye movement can be constrained to considerably less than +/- 0.5" horizontal and vertical, say for example +/-0.15" horizontal and +/-0.1" vertical. For the smaller eye travel distances a measurement can be made of the parallax error sensitivity per unit distance the eye moves (measured in MOA) near the center of the window and then this measurement can be compared with the measured parallax error sensitivity per unit distance from outside of +/- 0.15" and +/- 0.10", for example out to the +/-0.5" and +/- 0.35" distances used in the original measurement at the top of this post. At 1X it becomes a bit difficult to detect with the naked eye the small MOA shift for +/- 0.15" horizontal and +/- 0.10" vertical eye movement, but based on what I have seen so farI think a reasonable measured estimate can be obtained without complex apparatus.

(2) To see how much better a typical holo sight is at a 40 to 50 yard distance compared to shorter and longer distances, the same measurements described above can be made at several distances to target grid. There is plenty of room in the local gun store parking lot to do this, so I will see if they are willing to support such a test by loaning be a couple of holo optics for a few hours and I can bring some reflex sights.

(3) To see if the parallax error changes with eye relief distance, parallax error for the center of window and outside the center of window can be measured for a fixed amount of eye movement (in inches) at different eye relief distances.

By the way, your Razor G3 6-36x56 DLO Live review with Will was extremely helpful and it tipped me over to spring for a couple copies of this scope, one for a comp LR gas rifle and one for a comp LR bolt rifle. Absolutely phenomenal eye box and FOV just like you guys described and the other optical and turret/controls performance parameters are excellent. All the way up to 36x the sight picture is super stable, crisp and easy to get behind. The ones I have don't exhibit the mushy click issue that the first production batch had because I purchased a later batch after they fixed it so turrets have very solid, reassuring clicks with no detectable slop. Really like these scopes - thanks to you and will for yet another fantastic, accurate review.

koshkin · Apr 20, 2024

Milirad said:
At some point it would be nice to understand how a reflective curved surface projects and aim point that has a specific distance at which there is less parallax. At first blush it would seem that the eye movement would result in changes in the orientation of an infinite aim point line in 3-D space, originating at the front/target end of the sight window, that would not be sensitive to the axial distance along the line to the target, but given what you stated I'm sure there is something I'm missing on this.

Question for you: As I have been thinking about this topic it occurred to me that the eye relief distance to the sight could have a meaningful impact on parallax error. There could well be an eye relief distance where the POA sight lines from the rear of the curved reflective surface intersect, which might minimize the parallax error. Also, in separate potential effect, for a given fixed eye movement distance the angular movement of the eye with respect to the sight window center decreases as the eye relief distance increases. This may suggest that longer eye relief reduces parallax error sensitivity for a given fixed eye movement distance, albeit at the expense of FOV within the window. Is there an eye relief distance where parallax error is minimized, or is parallax error is insensitive to eye relief distance?

To answer your question: for red dots and holographics, the distance between the eye and the optics has no bearing on parallax offset.

If you chime in to one of my livestreams and remind me, I'll sketch out how this works.

ILya

Milirad · Apr 20, 2024

Great - thanks! Haven't been able to attend lately due to family/entertaining in the evening but will make a point for the next one if there is a little advance notice.

DeathBeforeDismount · Apr 20, 2024

This is like a bore scope thread. Someone who has no idea what they are doing, what they are looking for or how to use it comes along and posts some detailed analysis as if it means ANYTHING.

Instead of reading the mountain of proven tests done over the years by respected people/govs, they somehow think they are doing to bring something new to the table.

And here is the kicker, Parallax shift doesn't mean jack shit at CQB distances. Running around with an IR laser and dot/holo shooting people inside 25yards, mostly inside 10 yards, it doesn't matter. Virtually everyone cannot even shoot offhand inside of the shift.

This world salad is a waste of electrons. Not to mention you picked 2 of the biggest piece of shit optics (MRO and Chicomsun) to compare the eotech too.

This is what nerds do instead of going outside and actually shooting guns.

Edit: This dude hasn't even posted in 12 years. Its either some hacked account, or he got lose from his vault. He just decides one day hes going to grace us all with his testing out of nowhere............sus.

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EOTech Holographic Sight Parallax Induced POA Error Compared to Reflex Red Dot Sights

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