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Cheap Glasses

Posted: Fri Sep 15, 2017 2:39 pm
by Scrench
Hi guys,

Lots of people have been asking about shooting glasses lately, so I thought I'd offer a cheap solution.

I bought some clip-on flip-up sunglasses from WallyWorld, drilled a hole in the right lens that I predetermined the size I wanted from experimenting with paper, covered the lenses with black electrical tape where it was needed, then cut an old piece of bicycle inner tube to hang on the left frame arm as a blinder. This is on my prescription glasses, but you could do it with cheap sunglasses. I just don't see any point in paying hundreds of dollars for something that does exactly what mine do. The depth of field I get from the aperture size I selected makes my front pistol sight razor sharp (my prescribed glasses are for computer use, so close to medium work), and the target is now blurry enough that I can't see where my pellets hit, which takes away a lot of pressure from knowing I made a bad shot, which only causes more. If you want to add colored filters, make a trip to your local stage lighting supplier and buy some lens gels (called scrim) that come in a wide variety of transparent colors, more than you can get with shooting glasses. Total cost for my rig... $15.00

Scrench

Re: Cheap Glasses

Posted: Sat Sep 16, 2017 7:38 am
by william
Return with us now to those thrilling days of yesteryear.... The Lone Ranger rides again!

Re: Cheap Glasses

Posted: Sat Sep 16, 2017 4:42 pm
by David M
These glasses are not ISSF legal.
Too much tape.

Re: Cheap Glasses

Posted: Sun Sep 17, 2017 11:12 am
by Scrench
Bill, love the LR reference, but he could see with both eyes, which is why he was a better shot than me :)

So David, what would I need to do to make these legal? Not that I will ever enter an ISSF match, but I like to play by the rules.

Re: Cheap Glasses

Posted: Sun Sep 17, 2017 3:02 pm
by j-team
Regardless of the ISSF rules, all that black will not be helping you focus.

Try swapping the black tape for a light frosted material if you can. The more light entering both eyes the better for your focus ability.

Re: Cheap Glasses

Posted: Sun Sep 17, 2017 3:10 pm
by David Levene
Scrench wrote:...what would I need to do to make these legal? Not that I will ever enter an ISSF match, but I like to play by the rules.
The blinder over the non-shooting eye can only be a maximum of 30mm wide.

Side blinders are not allowed.

Re: Cheap Glasses

Posted: Mon Sep 18, 2017 4:38 pm
by Scrench
So what if I use only the flip-up shades from picture 3, no inner tube? The tape on the blinded eye is less than 30mm, the rest of the lens is just a regular sunshade.

Re: Cheap Glasses

Posted: Mon Sep 18, 2017 5:59 pm
by nglitz
j-team wrote:Regardless of the ISSF rules, all that black will not be helping you focus.

Try swapping the black tape for a light frosted material if you can. The more light entering both eyes the better for your focus ability.
This.

Re: Cheap Glasses

Posted: Wed Sep 20, 2017 1:35 pm
by SlartyBartFast
j-team wrote:Regardless of the ISSF rules, all that black will not be helping you focus.

Try swapping the black tape for a light frosted material if you can. The more light entering both eyes the better for your focus ability.
I've been using masking tape on my left glasses lens and a suction cup iris on my right.

Re: Cheap Glasses

Posted: Thu Sep 21, 2017 7:38 am
by Gwhite
All you need on the non-aiming eye is a very small blocker, it just has to be in the right spot to eliminate the double image of the target. All the science says you want equal amounts of light going into both eyes. This is why frosted tape works well.

Also, peripheral vision is important for balance & stability. If you completely cover the non-aiming eye (opaque or frosted), you will be more wobbly. I had one student who used frosted tape to completely wallpaper the non-aiming side of his safety glasses, and it made him dizzy. As soon as he switched to the recommended square of 3/4" wide frosted tape, he was fine.

If the tape/blocker is small enough, you can usually look under it when doing anything on the bench, like loading.

Re: Cheap Glasses

Posted: Thu Sep 21, 2017 8:25 am
by TenMetrePeter
or in this case simply roughen the non aiming side in the middle with wet and dry paper

The science isnt always right. My aiming eye is weak and I need a virtual blackout on the other eye or the glare of translucent blinder takes out the main image
Personal taste.

Re: Cheap Glasses

Posted: Thu Sep 21, 2017 3:48 pm
by Scrench
I'm going to try a strip of masking tape in place of the black tape I have over the left eye, no inner tube.

Re: Cheap Glasses

Posted: Thu Sep 21, 2017 8:45 pm
by william
TenMetrePeter wrote:or in this case simply roughen the non aiming side in the middle with wet and dry paper

The science isnt always right. My aiming eye is weak and I need a virtual blackout on the other eye or the glare of translucent blinder takes out the main image
Personal taste.
Sorry, buddy, the science is ALWAYS right. It's your responsibility to apply it properly to your specific case. That's technology.

Re: Cheap Glasses

Posted: Fri Sep 22, 2017 3:52 am
by TenMetrePeter
Not in my case buddy . I'm the one looking out and I can assure you I see better with a black blinder. Science has an empirical aspect as well as a theoretical one.

Science tells me what human pupils usually do and tells me what eye disease I have. Coping with it is as you say application of best remedy. So if science says I need equal light in each eye it is stupid. Equal light is a convention not science.

Science theory says you need +0.75 correction for pistol. A contributor recently said he shoots better with +1.25
He is right because he is the one looking through the lens.

Re: Cheap Glasses

Posted: Fri Feb 16, 2018 9:36 am
by ShootingSight
To get the best unaided depth of field and overall focus for your shooting eye, you want your pupil to be as small as possible. Humans do not typically have the ability to dilate their two eyes different amounts, so if both eyes see light, both pupils will constrict. If they both see dark, they both dilate. If one sees light and one sees dark, they will both go to some between value which is bigger than if both saw light. This is why it typically makes sense to use translucent tape, rather than black.

Obviously, if you have a condition that prevents you from doing that, you would be forced to accept shooting with a larger pupil with degraded depth of field.

The workaround is to make the hole in the tape for your shooting eye 1/8", or smaller. Depth of field in an optical system is based on the smallest aperture in the light path. So when I said 'unaided' at the top of my post, I was suggesting that your pupil was the smallest aperture you were looking through. And that is about 1/8" diameter in decent light. If the hole in the glasses you are looking through is 1/8, and your pupil is 1/8, you get the depth of field that goes with 1/8". If you cover your non-aiming eye with black, so your pupil dilates to 1/4 .... you still get the depth of field of 1/8, because it is the smallest aperture in the light path that counts.

Indeed, try 1/16" aperture. It will make the target and the front sight both be sharp at the same time.

I also recommend adding +0.75 added to your distance prescription, assuming your distance correction has your relaxed focal point at infinity (which is what it is supposed to do, if it is done right).