Wearing eyeglasses while using a riflescope

[Fast14riot]

Stay away from polarization when using riflescopes. It can introduce issues. Also, any tinting of eyeglasses reduces light transmission and can create issues with different coatings. Stay as clear as possible.

The tinting I got simply to reduce eye fatigue and improve contrast, which bothers me pretty much all the time. Curious about the potential issues with polarization. Going to search that up now.

 

[Turbulent Turtle]

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.

 

[FNSafari]

Chromatic Aberation

It happens in a lens system when the objective bends the light on its way to the eyepiece but all wavelenths aren't brought to a point focus..they are, to one degree or another, spread out. This shows as color fringing in the image. The faster the optical system the more this tends to occur. Modern glass and sometimes fluorite or triplet lens systems almost eliminate this. If you have a cheap rifle scope of high magnification you might see it as a purple haze round the outer edge of the eyepiece image.

Of course you know there is no such thing as color? All there is is light waves of various wavelengths that enter your eye are focused create an electrical pulse to your brain over the optic nerve, and our brain translates those wavelength signals as color. It's really an illusion but a beautiful one.

 

[Turbulent Turtle]

The tinting I got simply to reduce eye fatigue and improve contrast, which bothers me pretty much all the time. Curious about the potential issues with polarization. Going to search that up now.

Research is good. Please share the results.

 

[Turbulent Turtle]

If the glasses have no prescription/magnification and are polycarbonate, is there any CA?

Good question. My guess is that it's probably minimal, but my testing was first a simple "cheap" pair of Trivex safety glasses and if it worked out, I would get a full prescription pair. I have tried polycarbonate safety glasses in the past, and they were all unsatisfactory to my eye. This Trivex pair, just didn't seem to be there at all. And they are so light. At the next match, I will be testing with my prescription pair. This will allow me to look through the riflescope, look at the flags and be able to read properly, and protect my eyes.

At least, that's what I'm looking for.

ETA: Further research revealed that even with no prescription, there will be CA going through polycarb safety glasses and much less in Trivex. It seems just going through the lens material will create CA. Increasing the prescription will increase the CA. That tracks with my observations as my far vision prescription is almost nothing in my glasses. Thanks for the great question and prompting me to do further research.

 

[ELR LVR]

I will state again; coatings do nothing to correct CA. In optical terms, coatings only to control the reflection of light at the air/glass boundary, and they can reduce glare or ghost images (all products of reflectivity.) The do not imp[act or affect CA in any way, shape, or form.

There are also coatings to make the glass more scratch resistant, repel water, mud and dust and make coffee. But coatings don't do CA.

What I have read is
"

• Coatings can improve contrast by reducing stray light, helping to manage chromatic aberration.
• Properly coated lenses can enhance sharpness and detail, also helping to mitigating spherical aberration. - Where Light rays near the lens edge focus at different points than those near the center, leading to - a blurred image

 

[B Nettesheim]

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.

Such an important statement!!

 

[BoydAllen]

On the subject of coatings and CA.

https://www.cloudynights.com/topic/640775-a-single-layer-lens-coating-that-corrects-chromatic-aberration-right-across-the-visible-spectrum

 

[Rick300]

Good question. My guess is that it's probably minimal, but my testing was first a simple "cheap" pair of Trivex safety glasses and if it worked out, I would get a full prescription pair. I have tried polycarbonate safety glasses in the past, and they were all unsatisfactory to my eye. This Trivex pair, just didn't seem to be there at all. And they are so light. At the next match, I will be testing with my prescription pair. This will allow me to look through the riflescope, look at the flags and be able to read properly, and protect my eyes.

At least, that's what I'm looking for.

ETA: Further research revealed that even with no prescription, there will be CA going through polycarb safety glasses and much less in Trivex. It seems just going through the lens material will create CA. Increasing the prescription will increase the CA. That tracks with my observations as my far vision prescription is almost nothing in my glasses. Thanks for the great question and prompting me to do further research.

Do you have a link to the glasses you bought?

 

[Turbulent Turtle]

On the subject of coatings and CA.

https://www.cloudynights.com/topic/640775-a-single-layer-lens-coating-that-corrects-chromatic-aberration-right-across-the-visible-spectrum

Did you read the article to which the site links?

It's from 2018. 7 years ago.

The metasurface technology is not just a traditional coating but rather a fundamental reengineering of the lens surface at the nanoscale.

How Metasurfaces Differ from Traditional Coatings:​

• Traditional lens coatings are usually thin films designed to reduce reflections by controlling interference effects of light at the air-glass interface. They do not alter the path or dispersion of light inside the lens material.
• Metasurfaces are arrays of nanostructures (like tiny nanopillars) engineered to locally manipulate the phase, amplitude, and polarization of incoming light waves with great precision.
• This nanostructure engineering effectively reshapes how light travels and focuses through the lens, enabling correction of chromatic aberration and other optical imperfections beyond what multi-layer coatings or glass combinations can do.
• The metasurface modifies the effective refractive index at each point on the surface, allowing all wavelengths of light to be brought to the same focal point, something impossible with conventional coatings.
• It’s a surface-based optical element that complements or replaces complicated multi-element lens groups traditionally used to correct chromatic aberration.

In short:​

• It’s much more than a coating—it’s a nanoscale optical rework of the lens surface to create new, sophisticated light-bending behaviors.

This is why metasurface optics represents a new paradigm in lens design, going beyond coating technology to fundamentally control light behavior at a microscopic level, and it's probably outrageously expensive and extremely complicated.

I will stick with my comment: Coatings don't do CA.

 

[Turbulent Turtle]

Do you have a link to the glasses you bought?

This is the link to the frame that I got. It is an XL frame, I am a big person with a large head, so I got one of their biggest frames.

Clear Square Prescription Protective Glasses #744223 | Zenni Optical

Order online, unisex clear full rim plastic square eyeglass frames model #744223. Visit Zenni Optical today to browse our collection of glasses and sunglasses.

www.zennioptical.com

I started with that, and went looking for the 1.53 index lens that added another $30 to the $27 frame.

Just as a note. I went to the range today to shoot some pistols for a change. I had my Trivex safety glasses and it was great. I was shooting my Ruger MK IV Competition with a Holosun green reflex sight. I really can't tell any difference between naked eye and Trivex glasses. But slap on my regular polycarbs, and I can tell the difference. My full prescription Trivex glasses are on their way. Looking forward to that.

 

[Fast14riot]

Research is good. Please share the results.

Been doing some reading on effects of polarization in optical systems, which requires some inference for applicability to our purposes, as most everything I find is relating to digital photography/machine vision or in astrophotography. Digital camera sensors require circular polarizers for auto focus lenses to work properly.

General consensus is polarizers reduce light by 1-2 stops, increase detail and reduce reflections. Another interesting effect is the reduction of halation. This may be counterproductive to our purposes for seeing mirage due to perceived "sharpness" being improved which could reduce visibility of mirage. Need to do some testing on that.

However, in application for competition rifle shooting, our optical requirements are generally during daylight hours, bright FOV from a shaded firing point. Hunting and field use, light transmission and clarity (IQ) are paramount and reduced transmission can be detrimental.

In competition settings, the use of multiple telescopic viewing systems is not only common, but the norm. Trying to have a single optical device do everything required of a serious shooter is to be considered a folly. Spotting scopes with large objective lenses, long eye relief and lower magnification that can be focused closer than the target with contrasting OOF backdrops improves ability to see mirage while our primary aiming device mounted on the rifle is focused at the target, often lacking the OOF backdrop required to see mirage. But that doesn't mean CA isn't present either. High contrast situations can really show CA abundantly. I have seen this most when shooting steel or silhouettes. Ability to see the splash or accurately define the true edge of plate can be difficult with low quality glass. Sun shades can help by reducing flair within the optical train as light enters at a more narrow angle near the edges of the lens.

Anyway, this is an enlightening thread. I am going to continue using my polarized, tinted, mirror coated, prescription shooting glasses as its what I'm used to in competition, but will definitely do some testing in the future to see how it affect my IQ.

 

[chkunz]

I would like to thank the OP for starting this conversation. I think there is some significant technical optical information presented from some very knowledgeable people. I would like to start by thanking them for their contributions.

But for me, the undefined acronyms are a big block for my understanding of the technical information. I am a retired rocket scientist and have written many technical reports and the first rule is to define an acronym the first time it is used in a report. It is somewhat tedious but important if you would like for others to understand what you are presenting.

Best wishes
Clyde

 

[Fast14riot]

I would like to thank the OP for starting this conversation. I think there is some significant technical optical information presented from some very knowledgeable people. I would like to start by thanking them for their contributions.

But for me, the undefined acronyms are a big block for my understanding of the technical information. I am a retired rocket scientist and have written many technical reports and the first rule is to define an acronym the first time it is used in a report. It is somewhat tedious but important if you would like for others to understand what you are presenting.

Best wishes
Clyde

My apologies, the acronyms I used are common parlance in photography discussions, but not here. Forgot to switch brain modes.

FOV field of view
OOF out of focus (or out of frame depending on context)
IQ image quality
CA chromatic aberration

 

[JEFFPPC]

Lot of information in the post. But all that aside, at this point I see 6mm bullet holes at 400 and 500 yards much better with glasses off. All I am concerned with.

 

[Turbulent Turtle]

Been doing some reading on effects of polarization in optical systems, which requires some inference for applicability to our purposes, as most everything I find is relating to digital photography/machine vision or in astrophotography. Digital camera sensors require circular polarizers for auto focus lenses to work properly.

General consensus is polarizers reduce light by 1-2 stops, increase detail and reduce reflections. Another interesting effect is the reduction of halation. This may be counterproductive to our purposes for seeing mirage due to perceived "sharpness" being improved which could reduce visibility of mirage. Need to do some testing on that.

However, in application for competition rifle shooting, our optical requirements are generally during daylight hours, bright FOV from a shaded firing point. Hunting and field use, light transmission and clarity (IQ) are paramount and reduced transmission can be detrimental.

In competition settings, the use of multiple telescopic viewing systems is not only common, but the norm. Trying to have a single optical device do everything required of a serious shooter is to be considered a folly. Spotting scopes with large objective lenses, long eye relief and lower magnification that can be focused closer than the target with contrasting OOF backdrops improves ability to see mirage while our primary aiming device mounted on the rifle is focused at the target, often lacking the OOF backdrop required to see mirage. But that doesn't mean CA isn't present either. High contrast situations can really show CA abundantly. I have seen this most when shooting steel or silhouettes. Ability to see the splash or accurately define the true edge of plate can be difficult with low quality glass. Sun shades can help by reducing flair within the optical train as light enters at a more narrow angle near the edges of the lens.

Anyway, this is an enlightening thread. I am going to continue using my polarized, tinted, mirror coated, prescription shooting glasses as its what I'm used to in competition, but will definitely do some testing in the future to see how it affect my IQ.

I like your flair of the dramatic for sighting situations. Love the post.

You're absolutely correct about polarizers being 1 or 2 F-stops. As I was explaining to someone in a private DM exchange earlier, the difference between what works in photography and what would work for the mark 1 eyeball, is the fact that in photography, we have better exposure control. We have aperture control, shutter speed, and ISO. If I reduce the aperture, I can decrease the shutter speed to make up for it, or I can change the ISO (sensitivity), or a combination of both, and still have correct exposure. The reasons for reducing aperture would be to get greater Depth Of Field (DOF). If I use a polarizer, I do not get greater DOF, I just get less light to the sensor or film, and I make it up with the shutter speed of the ISO.

In a riflescope, reducing the aperture will increase the DOF, but you can't increase the shutter speed. The "ISO" will change as your pupil dilates but that takes a bit of time and only goes so far, especially for old geezers.

Top end optics have methods for controlling lens flare built-in. Over at Snipershide, the Dark Lord of Optics, keeps reminding everyone that March has the best flare control of all the scopes he's tested, and you can use a sunshade if you get too close to the sun when aiming. Point being, I don't think it's worth the 1 to 2 stops (50% or 75% reduction on light) into the riflescope to deal with something that's already being addressed.

I tried some circular polarizers for my Kowa 82SV, and it just made everything darker and brought in nothing that I could detect. I have circular polarizers for a few of my camera lenses, they provided for some dramatic pictures when I was shooting 35mm film, but it's been a quarter century since I've shot film. Nowadays, we can simulate polarizers in PP for digital pictures, and apply as little or as much as we want. (Crap, before I forget: PP = post processing, photoshop.)

I have come to the conclusion that I want absolutely nothing to (further) distort the image that comes from the eyepieces of my eye-wateringly expensive riflescopes. That's why I am so impressed with the Trivex stuff. I cannot discern a difference between naked eye and Trivex glasses.
Please continue to share your findings and experiences.

 

[Turbulent Turtle]

I would like to thank the OP for starting this conversation. I think there is some significant technical optical information presented from some very knowledgeable people. I would like to start by thanking them for their contributions.

But for me, the undefined acronyms are a big block for my understanding of the technical information. I am a retired rocket scientist and have written many technical reports and the first rule is to define an acronym the first time it is used in a report. It is somewhat tedious but important if you would like for others to understand what you are presenting.

Best wishes
Clyde

I must confess that my OP was part of a much larger paper I wrote on optics, and that this part was still under investigation and review. I just copied that small paragraph verbatim. My bad.
The reason I posted this part right away was because I thought it would be beneficial for shooters here. I am right in the middle of the experiment, but the results were so promising, I wanted to share right away.

I always try to define the acronyms I use at the start of the paper, and in this case, the first part of the large paper is a definition of terms. As you can guess, CA is discussed in great detail and the OP was just a final paragraph in the long paper.

Thanks for the reminder, and I went back and touched up the OP to put in the expanded acronyms at the start.

Just so you know, CA is more complex to explain than Max Q.

 

[SBfan]

I use an older Leupold 36X for short range (100 yd) BR and I shoot with glasses on. I have found that using a photography yellow filter attached to the scopes eyepiece does increase contrast which in turn makes the target "sharper". I had a good discussion with my eye doctor and learned that our eyes are oxygen hogs and need to rest periodically especially when looking through a scope. I have found it very helpful to use an eye patch which clips onto my glasses over my non shooting eye. It's a black plastic material and I have put some white tape on the side that faces my eye. This allows some light to be reflected into my eye so that the iris doesn't open up as it would if you were in a dark room. Having the patch allows me to shoot with both eyes open and lessens the strain on the shooting eye. These changes work for me and may or may not work for those shooting at 600 or 1000 yards, but they might. YMMV.

 

[Turbulent Turtle]

In the 1970s, I always had a SLR camera with me at university. I shot in B&W and was able to develop and print my pictures in a lab at the university. I just had to buy my own paper, the chemicals and equipment were supplied by the university. I ran my SLR with yellow filters and red filters, and of course, polarizers. The yellow filters did produce better contrast, which is why I was using them, but I had to compensate for them in the exposure. Thankfully the metering was TTL, so that was easy. (Crap, TTL = Through The Lens.) I sometimes used the red filter but that was much less often. The polarizer was fun to use, especially if you were looking into a lake or a river as it could penetrate the surface. With color film, I would use the polarizer, especially if there were clouds (in my coffee...). That could create some dramatic effects.

 

[Leo_B]

Apologies as I haven't read all, some of it frankly being above my level without thinking and studying, something I mostly avoid in retirement. But I am not wearing my glasses. Cataract surgery in Mar/Apr negated the need, other than drugstore cheaters for very small print.

So I get to wear a pair of safety glasses I ordered. Wiley-X. They have Sabre on one leg and no other identification. I forget all the ABC-XYZ coding but they are rated at a military level that is one above the normal safety glasses level. After ~60 years wearing glasses I am now, 5+ months later, getting used to not reaching to adjust my glasses if I need to read something or get access to scratch my itching nose or whatever.

Really looking forward to going and trying out these WX. Sorry for jumping in. Enjoy no glasses if you can.