TargetTalk

Hi,

Recently I started to shoot 50m free pistol.
I face some difficulty in some lighting conditions. Sometimes my groups are good and sometimes bad when it is cloudy.
I am thinking about shooting glasses but never used one, also no idea which on to go for, can someone enlighten me about how far these glasses and iris can help in achieving better scores.

rgds,

Shooting glasses are predominantly for distance correction to enable you to focus clearly on the foresight. You may also do better with a filter to cut down the light in bright conditions. I use a light brown one, others prefer yellow or rose coloured. It's really just a matter of trying some and seeing which work for you.

Rob.

Your question, leads to other questions, i.e. Your age?, Do you wear glasses now?, etc. If I were in your shoes, I'd see an optometrist and get your eyesight evaluated. Different colored lenses can help on cloudy days, if your eyes don't need correction.

Thanks for tips.
I am not wearing any glasses, 30 years old and I have normal vision, but not tested till now. I think I need to test and confirm.
Also I see some people wearing adjustable iris instead of glasses in issf videos. Do these iris comes with color filters.

rgds,

I have found that for pistol I need to use an adjustable iris to more or less focus my eye on the front sight. It works for me but maybe not for others.

I use the "Champion" brand glasses. They allow a wide range of lenses & filters, plus an iris, and it's pretty easy to swap lenses & filters in & out. My eyes are much older, and I need all the help I can get.

With younger eyes, you may be able to get away with just filters, but an iris wouldn't hurt. In some light conditions, you may just want to leave it wide open. The filters come in "steps", and the iris gives you the ability to fine tune things. Everyone's eyes are different, and what works for one condition or year will vary, so flexibity/adjustability is key.

Ideally, you want the relaxed focus of your eye to be on the front sight. For most people, that requires a corrective lens of ~ 0.75 diopters. That's where visiting an eye doctor who understands (or is willing to learn) about pistol shooting is important. Otherwise you get to invest in a lot of lenses and experiment to see what works. One thing you can try on the cheap is drug store reading glasses. You need to get the weakest ones you can find (probably 1 diopter) and see if that helps. Those with clip on dark glasses of different tints would be a start.

Assuming you use some sort of safety glasses, another option is stick on reading glass lenses. The problem with this approach is that they are typically stronger than you really want. You can also get reading safety glasses.

These are very straight forward photographic concepts, and you can even look up the formulas.

In shooting you want three things:
1. You want a big depth of field.
2. You want your focus (and hence your depth of field) to be centered between the front sight and the target, so the front sight just barely falls inside the near edge of your depth of field, at the same time as the target falls inside the far edge of the depth of field. This magic focal point is called your hyperfocal distance.
3. You want constancy of focus, because changing focus makes the front sight look slightly bigger/smaller, so you end up stringing your shots vertically if your focus is not constant. This third factor is the most important.

Your eye achieves focus at this hyperfocal distance when the ciliary muscle contracts and squeezed the lens in your eye, though another way to achieve this is to add the right power lens, shifting your eye's relaxed focus. If you can see distance fine, the correct power lens to shift your focus back is, as was pointed out above a +0.75 lens. This 3/4 diopter will shift your relaxed focus to 1.33 meters (diopters are the inverse of focal length).

When you are young, you can drive your eye to this focal point, as you get into your 40's, you have to strain to do it, and you cannot hold consistent focus, so it is a lot better to shift your relaxed focus, so your eye can stay relaxed while aiming.

It might still be a good idea to get your eyes measured, because if you need a slight distance correction, the correct lens for you would be the combination of the distance correction +0.75, though I would say if you don't wear glasses today, I'd give an 80% chance that the +0.75 will work.

Regrettably, reading glasses are very likely too strong. They start at 1.25 diopters, which will give you a GREAT front sight, but the target will be blurry.

Sorry but you do not need or want a big depth of field. You only need good focal acuity on the foresight, other elements can be slightly off focus.

You need to concentrate on the foresight and not the target so its better slightly out of focus.

Rob.

I fail to follow the logic that suggests less focus is a good thing.

As posted by others, the correct lens, if you go at it by trial and error, is +0.75, which is exactly what the photographic principles and optical math predict.

I can understand the notion that you might want to concentrate on the front sight, but that is a mental exercise, not an optical one. Even if you concentrate on the front sight, you want to focus at the hyperfocal distance of the rear sight.

If you want to do a cheap experiment to prove it, try this:

I just held up a pistol and a ruler. The front sight is 32" from my eye. That is 0.81 meters. Diopters are the inverse of focal length, in meters. So to shift a relaxed eye's focal point to 0.81 meters (assuming you do not wear glasses to see distance), you want the reciprocal, or a 1/0.81 lens, which is 1.23 diopters. Cheap reading glasses start at 1.25 diopters, so there is your answer. Buy a pair of 1.25 reading glasses, which will give you perfect focus on the front sight, and you will find (as many others have, and have posted) that 1.25 is much too strong for shooting, and while it gives a great front sight, the target is too fuzzy.

ShootingSight wrote:I fail to follow the logic that suggests less focus is a good thing.

You also fail to read the posts properly, no-where has anyone suggested less focus is a good thing.

I said you do not want a large depth of field. As you said it's a lot about being a mental thing. You want the foresight in focus so you mentally concentrate on it. Make the target sharp and your brain will flick to that, or flick between sights and target, without the shooter realising it.

That's why an iris is not a good idea, and if you look at the worlds best shooters, why you'll see almost none of them use an iris.

Rob.

I shoot better with an iris, but I could be the odd one out. My eye does not go back and forth between sights and target since they are all focused at the same time. It looks just like the text book drawings.

Are rifle shooters looking through a peep sight at a disadvantage?

RobStubbs wrote:
You also fail to read the posts properly, no-where has anyone suggested less focus is a good thing.

RobStubbs wrote:
...so its better slightly out of focus.

Must be an English language thing .....

For an elite athlete, their focus should be on the front sight and their attention should be on long term hold. And yes, you can do both. You can have your eyes focused on the front sight, and have your attention placed on hold. You should initially place your focus and attention on sight alignment, but prior to shot execution, your attention needs to shift to hold.