Rifle Scopes Tangent Theta 7-35

Until I bought my NF 7-35, I never realized how important properly setting the diopter is. The diopter adjustment on an NF ATACR is rather difficult to do properly since it has so much adjustment range. I initially had issues with getting parallax-free and achieving target focus. Thought the scope was damaged until I talked to NF who echoed the importance of setting the diopter properly. Once it is set correctly, focus and parallax-free operation converge beautifully.
 
Depending on the scope 100% in focus doesn't always mean 100% parallax free, again, diopter may play a role here so always good to verify.

There's another thread that goes into more detail on this. But yes, diopter does play a role in this. By definition, parallax error is only 100% eliminated when the target and reticle are aligned onto the exact same focal plane. That means they are both 100% in focus. And the byproduct of that is zero parallax error. If the diopter is set incorrectly, then that can affect how the target or reticle (or both) appear. The target and reticle could be aligned onto the same plane but one or both look out of focus because the diopter is set wrong. That's where the head bob/wobble technique comes into play to see if the target moves.

Me? I prefer to keep my head still and just twist the parallax knob until my target is focused. That means I nail my diopter setting during gun setup. And that also means I prefer a narrow depth of field so I can really see if my target is focused. I do this by sometimes watching the focal plane "travel" down range as I turn the knob. If a scope has a wide DOF it's harder to see that band.
 
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There's another thread that goes into more detail on this. But yes, diopter does play a role in this. By definition, parallax error is only 100% eliminated when the target and reticle are aligned onto the exact same focal plane. That means they are both 100% in focus. And the byproduct of that is zero parallax error. If the diopter is set incorrectly, then that can affect how the target or reticle (or both) appear. The target and reticle could be aligned onto the same plane but one or both look out of focus because the diopter is set wrong. That's where the head bob/wobble technique comes into play to see if the target moves.

Me? I prefer to keep my head still and just twist the parallax knob until my target is focused. That means I nail my diopter setting during gun setup. And that also means I prefer a narrow depth of field so I can really see if my target is focused. I do this by sometimes watching the focal plane "travel" down range as I turn the knob. If a scope has a wide DOF it's harder to see that band.
Spot on (y)
 
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Couple things here I'd like to address

True to a point, but may be more a matter of lazy fundamentals, even with a "forgiving" parallax you still need to make parallax adjustments if you want to be truly parallax free at your target. Also, diopter plays a role here, if you're shooting at 1000 yards (or whatever distance) and no matter what you do with the parallax dial you still get wobble I'd highly recommend fine tuning your diopter - I've had this happen to me on a couple scopes and minute changes in diopter cleaned it right up.

Depending on the scope 100% in focus doesn't always mean 100% parallax free, again, diopter may play a role here so always good to verify.

I'm not sure that "many" are fine with good enough, especially at this level of the game; however, I understand your point with regard to "good enough" vs. "precise". This is likely where the F Class/benchrest shooters have an edge (and need that edge because that is the level of their competition), most of them could care less about FFP but precise parallax control is very important when they're trying to shoot a 2 inch group at 1000 yards. Now that being said, I know many F Class shooters prefer to use much higher magnifications than do PRS shooters and claim that mirage isn't the issue that it is for many who shoot dynamic long range sports, and these same F Class shooters also prefer the "less forgiving DOF" so they can focus on a narrow band of mirage (heat waves) to judge wind at various distances before their target - in this regard less forgiving is actually a benefit for many in this field, but guess what, at higher magnifications DOF and parallax are going to be a lot less forgiving than at lower magnifications or I should restate that to say the "appearance" of DOF and parallax are less forgiving (that's the way magnification works, you are magnifying everything through the optic). So is it possible that something like the TT 7-35 might actually benefit both worlds - for the PRS shooter who stays around 15x or less the DOF and parallax (or appearance thereof) are going to be more forgiving but crank up that magnification to >25x and DOF and parallax are going to be more finicky which may be just what those shooters want...

A forgiving eyebox is always a benefit, I can't think of any situation where a forgiving eyebox would be a detriment. Maybe the above situation of using higher magnification in order to get narrow DOF and require more precise parallax adjustment is the solution. Unfortunately the drive for shorter and larger magnification ranges in scopes has created some unique designs, but the finicky eyebox in some of these optics is a real beast to bring under control, that being said I do not think this new TT 7-35, even though it is shorter than it's 5-25 counterpart, falls into this class, my brief experience with it showed it being forgiving in the eyebox arena.
I appreciate your point of view expressed above and I wanted to give an alternate view from my vantage point as a long time F-class competitor. I have dabbled in PRS, but at my age, it's not something for which I am suited. After reading you post, let's just stipulate that you have never shot F-Class and you are trying to fit it through your PRS experience filter.

In F-Class, shooters want the most magnification possible. We'll get to mirage in a bit, but let's deal with max mag for now. The reason people want to have the highest magnification possible is to be able to surgically place the reticle on the target. The precision of the shots have gotten to a ridiculous level in F-Open and right behind it, F-TR is experiencing the same. When the winners are decided by the number of Xs, this means the shooters want to get able to place their 15 or 20 shots in a 5-inch diameter circle at 1000 yards. To accomplish this, you need a fine reticle and large magnification, the reverse of what an FFP scope can deliver. This is why high-mag SFP riflescopes rule in F-Class.

Of course, you remember that the size of the exit pupil is a function of the diameter of the objective divided by the magnification. So, let's take my Majesta (8-80X56) scope as an example. When I'm shooting at 80X, the exit pupil is 0.7mm. I am here to tell you that if I am not perfectly behind the rifle, I see nothing in the riflescope. When I do get a sight picture, it's because I am positioned properly behind the rifle. There is no parallax to be experienced in those conditions. Also, F-Class shooters, the good ones, have an excellent gun handling regimen. They are positioned behind the rifle properly, and they repeat the position for every shot. They also perform a proper follow through. If you go to a match and observe the top shooters, you will notice the economy of movement in position.

If they do stop shooting during a string and then restart, they will take the time to get back into that proper position, because the eyebox is NOT forgiving, and that's a plus.


I like the way you dismissed mirage by stating the F-Class shooters claim "that mirage isn't the issue..." Mirage IS an issue but not all riflescopes handle mirage the same way. There are riflescopes that do a better job in mirage than others, and that's important. All good riflescopes do a great job when the conditions are nice, but when the mirage starts roaming, the IQ degrades; it's the rate of degradation that differentiate riflescopes. When the aiming black looks like a crazed amoeba on crack in your riflescope, you have to dial down the magnification. But if the aiming black is still round and the rings are distinct, you can stay at that magnification and shoot surgically. It doesn't mean the IQ is superb, but it's usable. The scopes that do better or put another way, don't get as bad as others, also show the mirage better to the eye; they detect it better and earlier. This is an advantage to the shooter because they can take what they observe and factor it into their hold. As a matter of course, I may play with the focus ring a little bit in periods of heavy mirage, but I don't do that for parallax adjustment. I use the focus ring for its intended purpose, focus the image.

I completely understand the desire for forgiving eyeboxes in PRS competition. There's a time factor involved, with movement, and difference distances in the same string. F-Class is much more static but requires a higher level of precision. One discipline is not better than the other, they are simply different.
 
I appreciate your point of view expressed above and I wanted to give an alternate view from my vantage point as a long time F-class competitor. I have dabbled in PRS, but at my age, it's not something for which I am suited. After reading you post, let's just stipulate that you have never shot F-Class and you are trying to fit it through your PRS experience filter.
Hey Denys, good to hear from you and you are correct, I've never shot an F-Class event but I am familiar with Benchrest style shooting (mostly back in the early 90's when 6 PPC ruled the roost - oddly enough the Hornady 6mm ARC reminds me a lot of the PPC).
In F-Class, shooters want the most magnification possible. We'll get to mirage in a bit, but let's deal with max mag for now. The reason people want to have the highest magnification possible is to be able to surgically place the reticle on the target. The precision of the shots have gotten to a ridiculous level in F-Open and right behind it, F-TR is experiencing the same. When the winners are decided by the number of Xs, this means the shooters want to get able to place their 15 or 20 shots in a 5-inch diameter circle at 1000 yards. To accomplish this, you need a fine reticle and large magnification, the reverse of what an FFP scope can deliver. This is why high-mag SFP riflescopes rule in F-Class.
I thought that's what I indicated in my comments but maybe it came across the wrong way - yes, precision long range shooters desire the magnification for precise shot placement.
Of course, you remember that the size of the exit pupil is a function of the diameter of the objective divided by the magnification.
This only applies at max magnification but exit pupil will change depending on the optical formula at lower magnifications.
So, let's take my Majesta (8-80X56) scope as an example. When I'm shooting at 80X, the exit pupil is 0.7mm. I am here to tell you that if I am not perfectly behind the rifle, I see nothing in the riflescope. When I do get a sight picture, it's because I am positioned properly behind the rifle. There is no parallax to be experienced in those conditions. Also, F-Class shooters, the good ones, have an excellent gun handling regimen. They are positioned behind the rifle properly, and they repeat the position for every shot. They also perform a proper follow through. If you go to a match and observe the top shooters, you will notice the economy of movement in position.

If they do stop shooting during a string and then restart, they will take the time to get back into that proper position, because the eyebox is NOT forgiving, and that's a plus.
Understood
I like the way you dismissed mirage by stating the F-Class shooters claim "that mirage isn't the issue..."
I feel this is taken somewhat out of context, what I said is "...claim that mirage isn't the issue that it is for many who shoot dynamic long range sports,". I never said just "it isn't the issue", I said that it isn't the issue that it is for many who shoot dynamic long range sports. I feel there is a difference there, but maybe not. I recognize these are two very different sporting events that have different needs based on the desired outcome and that the "issue" of mirage for the dynamic long range shooter is a different "issue" that mirage is for the precision shooter. Both encounter mirage, both address it a different way.
Mirage IS an issue but not all riflescopes handle mirage the same way. There are riflescopes that do a better job in mirage than others, and that's important. All good riflescopes do a great job when the conditions are nice, but when the mirage starts roaming, the IQ degrades; it's the rate of degradation that differentiate riflescopes.
I agree that, by and large, this is the case.
When the aiming black looks like a crazed amoeba on crack in your riflescope, you have to dial down the magnification.
I like your example here and may use that - "a crazed amoeba" 😆 I like to use the term "dancing target". Either way the shimmer of the heat waves causes distortion of the target.
But if the aiming black is still round and the rings are distinct, you can stay at that magnification and shoot surgically. It doesn't mean the IQ is superb, but it's usable.
I guess this is where I get confused somewhat. So you're saying that you'd rather have a lower IQ image at say 60x than a higher IQ image at 30x for example? I suppose the rule of diminishing returns may play a factor here - if the image is so bad at 60x then it is no longer helpful and you would back down on magnification whether it be the effects of mirage or optical anomalies within the scope itself?
The scopes that do better or put another way, don't get as bad as others, also show the mirage better to the eye; they detect it better and earlier. This is an advantage to the shooter because they can take what they observe and factor it into their hold. As a matter of course, I may play with the focus ring a little bit in periods of heavy mirage, but I don't do that for parallax adjustment. I use the focus ring for its intended purpose, focus the image.
I think this is what I was referring to above, using the narrow DOF and focus before the target to see what mirage is doing at that point (to gauge wind).
I completely understand the desire for forgiving eyeboxes in PRS competition. There's a time factor involved, with movement, and difference distances in the same string. F-Class is much more static but requires a higher level of precision.
Exactly
One discipline is not better than the other, they are simply different.
I would say that "better" is relative to the intended goal. For example, if ones goal is to better train for real world situations - then dynamic shooting sports like PRS, NRL hunter et al may be the "better" discipline, but if the goal is absolute precision at long distance then F Class and other 1k benchrest type comps are going to be the "better" discipline.

In the end I think we are communicating essentially the same thing, but maybe our dialect is a bit off which may cause some confusion :)
 
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(snip)
I guess this is where I get confused somewhat. So you're saying that you'd rather have a lower IQ image at say 60x than a higher IQ image at 30x for example? I suppose the rule of diminishing returns may play a factor here - if the image is so bad at 60x then it is no longer helpful and you would back down on magnification whether it be the effects of mirage or optical anomalies within the scope itself?

(snip)
In the end I think we are communicating essentially the same thing, but maybe our dialect is a bit off which may cause some confusion :)
Great response. I just want to respond to the paragraph above. I included your last line as a reminder, because it's so important.

Let me try to unconfuse you. What I was trying to convey is that while all riflescopes will have their IQ degraded by the mirage, this occurs at different rates for different riflescopes. Let me also say that NO riflescope is immune to mirage.

It has been noticed for a few years now that in periods of bad mirage most F-class shooters will dial down the magnification on their scopes from their maximum (usually something from 40 to 55X) because the IQ has degraded so much, and the aiming black is no longer round but is acting like the crazed amoeba I mentioned earlier. They will drop to the low 30s or in the 20s. AT this magnification, they no longer see the rings, just the black dot that is the aiming black. However, some riflescopes are still able to present an image of the aiming black as a solid round object and can still show the rings in the aiming black. The quality of the image has degraded, but the target is still usable at their preferred magnification. So these riflescopes allow their users to continue shooting at 50X, 60X and even 80X, while many others are now at 25X.

This is a well-known phenomenon in F-class circles for some riflescopes. Another trick that some people use is an aperture reducer, essentially blocking the objective with a cap that has a hole in it. The hole is dimensioned to reduce the amount of light by 50% (1 f-stop). Some are actually adjustable. This supposedly has the effect of reducing the IQ degradation from mirage. To me it makes the image too dark, and I do not notice any IQ improvement, but you do get a deeper DOF, of course. I don't need a deeper DOF.

I hope this helps.
 
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No offense but F-Class (I've been to a dozen+ matches) is just 🥱😴🥱

The Tangent Theta is scope built for PRS and other 'tactical' applications... Certainly NOT F-Class.
Of course. And I was not even thinking about the TT 7-35 for F-class. in any way shape of form. I was responding to general observations and statements from Glassaholic, and that's why I quoted his statements specifically. I apologize for the side-tracking. Carry on.
 
I like the TT because while it's clearly meant for tactical applications and lends itself well to PRS-style comps, it's also great for precise shooting. Maybe not for someone shooting bench rest or who shoots 100% F-Class. But I have one rifle and one scope. And while it definitely leans toward the tactical side of things, I still like punching one-hole groups with it.
 
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Great response. I just want to respond to the paragraph above. I included your last line as a reminder, because it's so important.

Let me try to unconfuse you. What I was trying to convey is that while all riflescopes will have their IQ degraded by the mirage, this occurs at different rates for different riflescopes. Let me also say that NO riflescope is immune to mirage.

It has been noticed for a few years now that in periods of bad mirage most F-class shooters will dial down the magnification on their scopes from their maximum (usually something from 40 to 55X) because the IQ has degraded so much, and the aiming black is no longer round but is acting like the crazed amoeba I mentioned earlier. They will drop to the low 30s or in the 20s. AT this magnification, they no longer see the rings, just the black dot that is the aiming black. However, some riflescopes are still able to present an image of the aiming black as a solid round object and can still show the rings in the aiming black. The quality of the image has degraded, but the target is still usable at their preferred magnification. So these riflescopes allow their users to continue shooting at 50X, 60X and even 80X, while many others are now at 25X.

This is a well-known phenomenon in F-class circles for some riflescopes. Another trick that some people use is an aperture reducer, essentially blocking the objective with a cap that has a hole in it. The hole is dimensioned to reduce the amount of light by 50% (1 f-stop). Some are actually adjustable. This supposedly has the effect of reducing the IQ degradation from mirage. To me it makes the image too dark, and I do not notice any IQ improvement, but you do get a deeper DOF, of course. I don't need a deeper DOF.

I hope this helps.
I appreciate that Denys, it does help me (and hopefully some others) in understanding a little more. (y)
 
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Are you telling me one is none and two is one? 🤔 💸 😆
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Is there an ETA from Armament on orders placed now?
I still have outstanding scopes from January -March 2023 Orders. I should start seeing these trickle in now and anything I don't already have on order placed today is 90-120 days out.

Lots of 525s immediately available though.
 
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We received a shipment of Tangent Theta 7-35x56 JTAC and Gen 3 XR Fine models yesterday and they have been running out the door :)
Call 916-670-1103 or order below to grab one of these hard to find scopes.

 
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