I have seen the results of case failures that would have resulted in eye damage and possible vision loss, if the shooter had not been wearing glasses.
I am slightly nearsighted. My glasses are bifocals with lines,d which became a requirement when I hit my early 40s. None of this causes me any problem for my shooting, not image quality, or chromatic aberration.
I have a fair amount of background in the basics of optics and vision. Sometimes I get the impression that some shooters forget that we are not using our rifle scopes for bird watching or photography.
IMO, assuming reasonable image sharpness, the most important quality of a scope used for target shooting is that it not have any shift in point of impact at a given setting. This is not something that can be assumed based on price tag.
Many many years ago, I made a scope rack such that five different 36X scopes could be mounted, side by side, with the whole thing on a sturdy portable table, shooters could adjust the scopes to their own eyes and take as much time as they wanted to view a target through each of the scopes. All of the ring sets were adjustable. I used a single, centered scope to adjust them so it was centered on the same target. Perhaps it is time for someone to do the same thing. Back then 36X was the highest power available for a fixed power scope. The scopes were a Leupold, two different Tasco designs, a Bausch and Lomb, and a Weaver T model.
Have any of you experimented with light tint yellow filters on your objective, eyepiece or as glasses lens tint, for improving contrast and apparent sharpness, particularly in overcast conditions?
Thank you for your contribution.
I started this thread by stating my hypothesis that CA is a major contributor to the degradation of the IQ in a riflescope from shimmer/mirage. My contention is that CA intensifies the shimmer, and if your riflescope is able to control or eliminate CA, it retards the IQ degradation. I further postulated that polycarbonate glasses produce their own CA and thus add to the IQ degradation. I stated that the IQ deteriorates when I wear glasses. I looked to a solution that would allow for protection of my eyes AND not further screw up the IQ of my riflescope.
My current solution is Trivex lenses. I experimented with them and discovered that I could not see a difference between naked eye and Trivex safety glasses, but I could see a difference between Trivex and polycarbonate lenses. To me, that was a win, and I passed it along.
Shimmer/mirage will mess with the IQ of any riflescope, the image from a Majesta in mirage conditions will not win any photograph prizes; that is my goto way of setting expectations. On the other hand, in a Majesta, the aiming black will stay round, and the rings will stay distinct and round even at high magnification. As an F-Class shooter, I live by the rings. That is how I aim my shots.
Using a higher magnification allows the shooter to be more surgical in the placement of the shots. Especially for us old geezers (>70). But when your riflescope gives you an animated image of darkish gray amoeba seemingly on crack surrounded by hazy mishappen rings, instead of a round aiming black with concentric rings, you are forced to dial down the magnification and incur the loss of precision in your aim.
So, when you have a riflescope that controls the CA very well, and there are few of them, the last thing you want is to introduce more CA with your glasses.
I have played with filters in front of objectives some years back. I tried light yellow, dark yellow and red filters. I did not detect any advantages in any conditions at that time. I gave up testing those after a few months. Before someone starts playing with them, let me caution you about a few things. Photography filters are NOT rifle certified. You rarely see a camera experience the recoil that a riflescope will shrug off. Filters can and do break and that could mess up your objective lens and its coatings. Placing a lens in front of your most important lens (in terms of IQ), is not "a good thing" (TM). You are messing with the light path and the optical formula. It could conceivably cause a shift in the aim. If you really want to try filters, consider using a filter behind the eyepiece or on your glasses.
Also, filters will cut down on the light, but will NOT increase depth of field.