Re: Please describe S&B tunneling.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: David S.</div><div class="ubbcode-body">I wasn't going to get into this any further because it will most likely result in hurt feelings like the last times, but I'm not going to have anyone suggest that I'm somehow manipulating things here to make someone look bad.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Aries64</div><div class="ubbcode-body"><span style="font-weight: bold"><span style="font-style: italic">David S.</span></span> posted <span style="font-weight: bold"><span style="font-style: italic"><span style="color: #FF0000">simulated FOV images</span></span></span> to illustrate the PMII's tunneling effect at low magnification. However, the tunneling effect in <span style="font-weight: bold"><span style="font-style: italic">David S.</span></span>'s <span style="font-weight: bold"><span style="font-style: italic">simulated FOV</span></span> images are just that - <span style="font-weight: bold"><span style="font-style: italic">simulated</span></span>.</div></div>
Yes they are simulated as I pointed out in the other thread. I don't have access to both scopes, and if I did, people would doubt the photos. In fact, it is easier to do a fair comparison with simulations, because you can't skew anything with different camera positions. It would be nice if someone who owns the scope in question could shoot a through the scope vide while zooming from max. to min. magnification, <span style="font-weight: bold">while keeping the camera at a fixed position behind the ocular.</span>
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Aries64</div><div class="ubbcode-body">If you look closely at the two images you'll notice that the size of everything within the FOV is consistent between the two images, and that only the FOV varies.</div></div>
Yes, that is absolutely correct, simply because in both images, <span style="font-weight: bold">the magnification is the same</span>, so objects have the same size, and the FOV difference at the same magnification is what causes the tunneling effect.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Aries64</div><div class="ubbcode-body">While the reticle and the objects within the FOV are <span style="font-style: italic">proportionally correct</span> (as they always are in a FFP scope), <span style="text-decoration: underline">leaving the size of the reticle and the other objects in view the same size in both images <span style="font-style: italic">while manipulating the FOV</span> seems to exaggerate the tunneling effect.</span></div></div>
There are three variables here, magnification, FOV and reticle subtensions. Magnification is identical, so the target images are the same size. Reticle subtensions are also identical because I assumed both scopes to be FFP, so the only difference is in fact FOV, and that difference is taken straight from the spec sheets, <span style="text-decoration: underline">I'm not "manipulating" FOV. I'm strictly putting the numbers into a visualization</span>.
This does not "seem to exaggerate" anything, it just shows what is there, under the same settings so that it is directly comparable (while RobO1s images remove any clues of the tunneling effect, since an image that is cropped to the edges of the field of view contains no information at all whether it was taken at 5x or 7x when tunneling is present in that magnification range, as I have explained in detail
here).
<span style="font-weight: bold">You are listing exactly the criteria that make these images comparable and make it sound like that was some kind of manipulation on my part. I cannot reject that allegation strongly enough.</span> That is like saying that the <span style="font-style: italic">"simulation"</span> of the comparative length of two scopes made it <span style="font-style: italic">"seem like one is longer than the other because they are both depicted at the same scale"</span>.
I've always held your posts here in high regard and you seem to be a person with a lot of technical understanding. Please reconsider what you have written, you are proving my point while claiming the opposite.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Aries64</div><div class="ubbcode-body">As has been said here and in numerous other posts - <span style="font-style: italic">in-person</span>, the tunneling isn't nearly as dramatic as <span style="font-weight: bold"><span style="font-style: italic">David S.</span></span>'s simulated FOVs' suggest.</div></div>
It is hard to argue with personal impressions, that's why I stick to numbers. The only explanation for a dramatically different personal impression (that I don't share) is that the eye relief (or the width of the eye relief band) changes at low power so you can change the position of the eye, which could affect the width of the black ring around the target image. This may happen unconciously. However, this will <span style="font-weight: bold">not</span> change the observable FOV.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Aries64</div><div class="ubbcode-body">All of the above said, the most accurate way to describe the tunneling effect in a PMII is to visualize or draw two (2) concentric circles, one slightly smaller than the other. The larger <span style="font-style: italic">(outside)</span> circle represents the FOV (Field of View) you get <span style="font-style: italic">without tunneling</span>, while the smaller <span style="font-style: italic">(inner)</span> circle represents the reduced FOV (Field of View) caused by the "tunneling"</div></div>
What you are describing is exactly what my images show. I have just translated this into proportionally correct images. </div></div>
<span style="font-weight: bold"><span style="font-style: italic">David</span></span> -
First off, I feel it's unfortunate that you felt compelled to post in this thread in order to "defend" something that you posted here previously. There are a lot of sensitive egos' here, and I've found that its' sometimes hard to get a point across without injuring someone's ego - even when what you're trying to put forth is proven fact. As you've probably read I own two (2) PMII 5-25X[556mm] scopes and while they "tunnel" between 5X-7X my feelings are not hurt in the least nor does the tunneling bother me.
I'd also like to make it clear that I did not mean to imply that you purposefully manipulated the images in order <span style="font-style: italic">to make someone look bad"</span> in my previous post (the one you quoted me in). That was not my intent, so if you inferred it that way I apologize. Based on my experience (I haven't correlated the numbers on paper), the actual <span style="font-style: italic">"in-person view"</span> and your simulated image views look very different, and I was simply trying to point-out that out. Nothing more, nothing less.
As far as not having access to both scopes, I can't help you there. I sold my Premier 5-25X[56mm] a couple of years ago. And in regard to people doubting the photos thats' their perogative and problem. I know that I've done plenty of shit in the past and can still do things that people say isn't possible. I and a few others are the only people who will ever know the truth. People believe what they choose to believe when they choose to believe it, period.
Now, and I'm embarassed to admit this (especially since I generally have a pretty good technical understanding of how things work), but in regard to the magnification being the same between the images I thought that the simulations were of a PMII 5-25X[56mm] at 7X (image on the left) and a PMII 5-25X[56mm] at 5X (image on the right). Now that I know that the images represent a non-tunneled 5X view (on the left) and a "tunneled" 5X view (on the right) I see why everything within the image views are proportionate. That makes sense. I sold my Premier 5-25X[56mm] and I don't have one handy to compare it to, but looking recalling from memory the two images are probably a pretty accurate representation. Again, my apologies for temporary dyslexia and faux pax'.
Keith