Shooting Glasses - Another Question

[shadow]

I am visiting my optometrist in one week. Two years ago she let me bring my air pistol to her office and did a pretty good job of prescribing/fitting "shooting" lenses in regular frames. I bought a pair of older style Knobloch frames from a shooter on this list. I want to get lenses made for these frames.

My question is: if my Air Pistol and Free Pistol have the same sight radius, Free is shot at 50M and Air at 10M, would a different precsiption be required for each discipline? I am Farsighted and by now my distance prescription is around a +4.75 with an additional + for intermediate or reading which I guess is pretty strong. Also, what material provides the best optical clarity - plastic or polycarbonate?

BTW, I have read Norman Wong's article.

Thanks!

[GOVTMODEL]

I

My question is: if my Air Pistol and Free Pistol have the same sight radius, Free is shot at 50M and Air at 10M, would a different prescription be required for each discipline?

No (probably), as you're still trying to see the sight clearly. At least that's how it works for me:-)

[Fred Mannis]

I am visiting my optometrist in one week. Two years ago she let me bring my air pistol to her office and did a pretty good job of prescribing/fitting "shooting" lenses in regular frames. I bought a pair of older style Knobloch frames from a shooter on this list. I want to get lenses made for these frames.

My question is: if my Air Pistol and Free Pistol have the same sight radius, Free is shot at 50M and Air at 10M, would a different precsiption be required for each discipline? I am Farsighted and by now my distance prescription is around a +4.75 with an additional + for intermediate or reading which I guess is pretty strong. Also, what material provides the best optical clarity - plastic or polycarbonate?

BTW, I have read Norman Wong's article.

Thanks!

Acrylic gives better optical clarity than polycarbonate which is more resistant to impact. BTW, I have been ordering my 37mm diam Knobloch prescription lenses from Neil Steppe at ISS. Prices are better than what I can get locally.

One other point: anti-reflection coating to increase light transmission and reduce reflections is expensive, but I have found it well worth the cost.

[Shooting Kiwi]

Absolutely! Anti-reflection coating is a must!

Since you are supposed to be focussing on the front sight, not the target, if the distance, for each pistol, from eye to front sight is similar, the same prescription is appropriate.

Have you got an adjustable iris for your specs? You need one.

[Guest]

Absolutely! Anti-reflection coating is a must!

Since you are supposed to be focussing on the front sight, not the target, if the distance, for each pistol, from eye to front sight is similar, the same prescription is appropriate.

Have you got an adjustable iris for your specs? You need one.

An adjustable iris is essential. How else will the other shooters know you are really cool?

[mikeschroeder]

Hi

O.K., I give what does an adjustable iris do anyway? I can focus on the sights and then can't depending on what kind of day I've had, how dry the contacts are etc.

Mike
Wichita KS

[Spencer]

Hi

O.K., I give what does an adjustable iris do anyway? I can focus on the sights and then can't depending on what kind of day I've had, how dry the contacts are etc.

Mike
Wichita KS

Mike,
this is a common problem.
The eye can change in its 'relaxed' focus by +/- 1/8 dioptre during the day; add in the manufacturing tolerance on most lenses (up to 1/4 dioptre for some) and getting a lens that will bring your relaxed focus to the front sight is a bit of a lottery.

On a good day, the accommodation of your eye can cope with the day-to-day variation and any discrepency in the lens - on a bad day this tolerance stacking becomes more noticable.

Many years ago, Don Nygord told me he had +1/8 and -1/8 lenses that he would add to his shooting lens as needed on the day.

An iris can help by 'stopping down' the vision and increasing the percieved depth of field.
Unfortunately, some shooters try to use the iris to bring the target and front sight into simultaneous focus, instead of bringing the front sight into focus...

Spencer

[Neil Foster]

An iris can help by 'stopping down' the vision and increasing the percieved depth of field.
Unfortunately, some shooters try to use the iris to bring the target and front sight into simultaneous focus, instead of bringing the front sight into focus...

The other advantage to the iris is to cut down bright sunlight, I am sensitive to very bright light. Although I have a gray sun lens to snap on my Knobloch's I find that I have better clarity of the front sight when using the iris to "cut" down the light. At Ft. Benning we shoot from inside a building that is not bright, through a door to the 50 meter target outside. That sometimes give my eye adjustment fits. And as Fred pointed out Neal Stepp has excellent pricing and service, in addition he is a genuinely nice guy to do business with. He is very knowledgeable about shooting glasses.
As was said the anti-reflective Zeiss coating is not cheap, but it is worthwhile.
Neil

[Shooting Kiwi]

An adjustable iris is essential. How else will the other shooters know you are really cool?

Coloured filters!

Also, as others have suggested, particularly for us oldies, a selection of lenses, in 1/4 or 1/8 diopter increments would be useful. So would be an over-full wallet.

[Non-iris]

Absolutely! Anti-reflection coating is a must!

Since you are supposed to be focussing on the front sight, not the target, if the distance, for each pistol, from eye to front sight is similar, the same prescription is appropriate.

Have you got an adjustable iris for your specs? You need one.

An adjustable iris is essential. How else will the other shooters know you are really cool?

There are some drawbacks. An adjustable iris reduces light, which increases the diameter of the eyes own "iris", whick decreases depth of view...
I feel much more comfortable using colored lenses. My two adjustable irises (two diff. diameters) have seen less use during the last years. My scores have increases some during same period.
I feel an iris, which has to be shocked quite a bit to achieve notiseable increase in dept of view, is straing my eyes more than the colored (rotate into line of view type (Knobloch)).
I strongly feel, from years of experience, that use of an adustable iris is no shortcut to omproved scores.
But that is just my opinion.

From tha last olympics 50 m pistol event, final: was there many adj. irises in use?

An adjustable iris looks cool? IMHO it looks like over-gadgetery.

[AAlex]

An adjustable iris reduces light, which increases the diameter of the eyes own "iris", whick decreases depth of view...

The diameter of the pupil has no effect whatsoever on the depth of field if the iris diameter is smaller and vice versa (it should be rather obvious as to why).

From tha last olympics 50 m pistol event, final: was there many adj. irises in use?

Perhaps because the range lighting conditions do not require the use of iris? How many of those finalists do you think do not own one?

I strongly feel, from years of experience, that use of an adustable iris is no shortcut to omproved scores.

So let me guess: if I can't see front sight well due to eye or lighting conditions, instead of using the iris and eliminating the limiting physical factor I should "work harder"?


Your years of experience don't jive well with my common sense.

[gunnery]

Verry intresting, buth sorry, in german: http://www.mueller-manching.de/seminar.htm

[Shooting Kiwi]

There are some drawbacks. An adjustable iris reduces light, which increases the diameter of the eyes own "iris", whick decreases depth of view...

...however, you have voluntary control of the mechanical iris. It should not be constricted enough to make the sight picture dim. The depth of focus is effectively controlled by whichever aperture is smaller.

Note: the mechanical iris should be as close to your eye as possible.

It's a juggling act. Like most things in this game, there's the science and then there's what works for you - if only they were more similar!

[sagara]

Hi,
I have never used a shooting glass. but I bought one.
so pls tell me when I need to adjust the irish am to watch the target or the front sigth throught the irish.
I have seen poeple just watching the out side.
rgds
sagara

[Richard H]

If you are going to use the iris, leave it as open as you can, and just adjust it to get the front sight in focus if needed. You still want the target to be blurry and fuzzy.

By stopping down the iris you are increasing your depth of field, just like in photography a smaller f-stop (bigger number) increases the depth of field. Basically if you are using the iris you'll have to adjust it for various lighting conditions.

[Non-iris]

Your years of experience don't jive well with my common sense.

Probably ´cause your common sense is way superior to all other peoples common senses, combined.

You are right, Alex, I was not born with any common sense, and have not acquired any later on either..
Sorry about that.

But maybe, just maybe. my 50 m scores are better than yours? I do not know, I am just guessin´.
I do not use any adjustable iris, and hence, my scores are hard to beat....:-)
Unless you are a top notch ( team-member) that is...

[Richard H]

Lets have a big pissing match over someone else using an iris.

Some people use an iris and others dont.

I tried one for a while and no longer use one myself, but I wouldn't discourage anyone from trying one.

Some people just use the iris almost fully open to help with the repeatablility with head position.

Thera are some at the eite level that use an iris and there are some that don't.

[paw080]

Ha Ha...Richard, I totally agree with you; some like 'em,some don't.
There actually is a great venue for irises, that is in AP Silhouette match
shooting. The iris brings all sight elements into clarity. I still direct my
attention on the front sight and try to hold sight aligment, with the very
clear silhouette bouncing around. The picture is like looking at a flat two
dimension target with the elements moving about. I also shoot single
handed instead of the allowable two handed hold that the rest of the shooters
use. Just to maintain integrity with 10 meter AP.
Tony G

[sagara]

Hi,
Thanks for the comments.
for me after one or two seconds the front sight get blurred.
this happen in both free & Air pitols.
then what I do is forcus the target & come back to the sight.
but if I can reduce that time..?
would the irish help me to get the sight clear.
I have not seen many people use irish for Air pistol.
but when I feel light is too much for me I feel like use it for Ari pistol.
pls correct me.

rgds
Sagara

[Spencer]

Hi,
Thanks for the comments.
for me after one or two seconds the front sight get blurred.
this happen in both free & Air pitols.
then what I do is forcus the target & come back to the sight.
but if I can reduce that time..?
would the irish help me to get the sight clear.
I have not seen many people use irish for Air pistol.
but when I feel light is too much for me I feel like use it for Ari pistol.
pls correct me.

rgds
Sagara

If you can focus at the target at 50m, you definitely need a different script

Spencer