Shooting Glasses Lens Selection

[dulcmr-man]

I'm new to 10m air pistol and I'm thinking about buying a pair of Champion glasses. Do most folks who use these buy a "custom" lens from an optometrist to start with? I see that one can also buy lenses in quarter-diopter increments, i.e., 0.25, 0.5, 0.75, etc. However, I've read that these lenses are intended to compensate for differences in lighting etc., and are intended for use with a basic lens that focuses the eye on the front sight. What's the best way to move forward? Custom lens or a series of standard quarter diopter lenses then experiment? Thanks in advance for your help

[Tim S]

I've not heard of changing your prescription to compensate for light, but then I'm a rifle shooter. The dioptre of the lens determines your focal distance, which should be independent of light levels. If you buy a custom lens then the optician will take your regular prescription and add correction for your desired focal distance; for rifle shooting this is typically +0.5 (I say typically as it's related to sight radius). My regular prescription is +1.0, so my shooting lens is +1.50. The +.25/.50/.75 lenses will just correct for the right radius, and won't take into account your regular correction.

If you normallyb wear glasses, I'd think about a custom lens.

If you have an astigmatism, then I'd also suggest a custom lens.

[Rover]

You need your regular prescription plus a correction to bring your focus to the front sight. It's nice if it's all in one lens and more trouble-free.

If you don't have a regular prescription, maybe you need one and don't know it.

Find out from your eye doctor and get a prescription. Some think this is too much trouble/expense, but when you consider the effort/expense you put in the sport, it's worth it.

[Gwhite]

You generally adjust for lighting with an aperture or with clip on filters, not with the lens. That said, I've found that with my old eyes, I do better with a slightly different lens for indoor shooting than for outdoors where there is a lot of light. I now have two sets of glasses for that reason.

As you age, your eyes will vary, and you will need to tweak your lens from time to time. I wear contact lenses, and my shooting eye is normally set up for distance vision. I need between +0.75D and +1.25D depending on how well my contact lenses correct my vision.

Another variable is that the lenses aren't ground perfectly. You can have two "+0.75D" lenses that are easily off by +/- 0.125D (or more), so you can run across a "+0.75D" lens that is actually the same as a "+1.0D" lens. My eye doctor let me check a handful of lenses on his "lensometer" (which is only marked off in 1/4D graduations), and they were all over the map. I am a curious sort who likes to tinker, and I eventually set up a measurement system of my own using the length of my basement & a small light source. If you move the lens back & forth until it focuses on the far wall, you can calculate the diopter rating. Even that isn't perfect, because you are measuring the whole lens, and you really only look through the center. I've had some lenses that distort the image slightly, so I know they aren't always ground uniformly. It may be that with modern computer controlled optical lathes that they can do better than years ago, but I don't trust any lens I haven't measured myself.

I now have a sizeable collection of lenses of known correction that I can swap in & out until I get the image I need. The older I get, the less adaptable and fussier my vision has become, and I have found significant improvements with just 0.125D changes in my lenses.

[dulcmr-man]

Thanks to everyone for posting a lot of informative information. I read about the lens change to compensate for light changes in some of Don Nygord's tips on shooting. Like others who posted, he mentioned that "custom" lenses are often not ground correctly. I'd like to hear more about calculating diopter if Gwhite is willing to post that data.

Thanks again for the advice.

[paw080]

Hi Dulcmr, Don't sweat the diopter stuff; Simply follow Rovers advice and get thee
to thy Ophthalmologist, and get a prescription for the distance to your front sight,
as viewed while in your shooting stance. If the eye care practice has opticians on
their staff, they can have your lens cut to fit your lens holder.
It only cost me $35 for a lens because the refraction was done by the practice.

I almost forgot to mention this, but I believe compensating for light conditions is
best done by changing the width of your pistol's rear sight notch. Hopefully your
AP does have a rear sight width adjustment

Tony(Corona-Calif.)

[David M]

Print the attached article from Dr Wong and take it to you Optometrist.
Basically you need to de focus your distance script by +0.5 to +0.75
diopter.
For indoor shooting you will not need any tint, unless the range is
poorly lit by in phase fluro lighting.

[Gwhite]

Because I am not as young as I once was, I can't remember what the heck I did from day to day, so I take lots of notes on stuff I may have to do every few years. I've attached my notes on how I measure my lenses. It's very specific to my basement & gear I have kicking around, but it has the formulas and general procedure documented fairly well.

[spektr]

http://shop.shootingsight.com/Test-Lens ... ns-Kit.htm

[Gwhite]

http://shop.shootingsight.com/Test-Lens ... ns-Kit.htm

Interesting. I wonder what the tolerances are on the lenses. One issue is that you need to hold them at just the right distance from your eye to match where they would sit in your frame..

My eye doctor actually uses a huge kit of lenses like that with a special glasses frame they fit into. He says he gets better results than with the big contraption with lens wheels they park in front of your face.

http://www.amazon.com/Optometry-Opticia ... B007UKHFUG

http://www.amazon.com/Optic-266PCS-Meta ... B7QSPJ2BJ4

I found a couple places that sell trial lenses, but I couldn't find any indication of what the typical tolerances are.