Using an Iris

[jjgun]

I was wondering how many people use an iris for AP competition. I tried a friend's over the weekend and was suprised at the difference it made. Also, for use with regular glasses, is there a preference between the flip-up type and the suction cup type?

[DaFont]

Hello,
I shoot a league in Connecticut with a fixed Iris (Hawkeye) and an Anshutz LP@. An iris makes a substantial difference. It just allows parallel beams of light through and reduces scattered light making the sight picture quite a bit clearer. I just ordered an adjustable made by Gehmann from Champions to replace my fixed iris. An iris will clear up any open sight.
Shoot 10's
DAF

[Lanning R. Hochhauser]

That was my progression. I wear distance glasses so I purchased a full size pair of reading glasses that got me focused at about the right distance (the from sight) then I attached an IRIS for finetuning. It served its purpose however stopping down an IRIS also reduces the light that gets through. On a dimly lit range that can be a problem. I now use shooting frames with the correct lense. I also have an IRIS on the frames but hardly ever stop it down.
DoctorD

[2650 Plus]

In MHO an iris can be a help provided its being used to help you focus on the front sight. If you think it will help you see both the front sight and the target better I'm afraid you are going to be dissapointed. Some of the hype in advertising may lead you to believe this can be accomplished, But I am convinced you will be better off just focussing on the front sight and letting the target take care of itself. Remember the target is the only thing that is perfectly still and every thing else is moving. What do you think you should be concentrating on seeing , and what can you safely Ignore? Good Shooting Bill Horton

[RobStubbs]

In MHO an iris can be a help provided its being used to help you focus on the front sight. If you think it will help you see both the front sight and the target better I'm afraid you are going to be dissapointed. Some of the hype in advertising may lead you to believe this can be accomplished, But I am convinced you will be better off just focussing on the front sight and letting the target take care of itself. Remember the target is the only thing that is perfectly still and every thing else is moving. What do you think you should be concentrating on seeing , and what can you safely Ignore? Good Shooting Bill Horton

As Bill mentions iris's look like a wonderful invention when you first try them - everything is clear and in focus. BUT that is not what you want. You can only focus properly on one thing at a time and and an iris really confuses that so you keep flitting between, rear sight, fore sight and target. I would personally advise you to bin (trash) the iris and get a shooting lens made up that allows you to focus easily on the foresight and have a slightly blurred target. Your results will improve because of it.

Rob.

[Fred Mannis]

Rob,
Why do you assume that use of an iris automatically leads to a sharpening of the bull and incorrect sight picture? Properly adjusted, an iris can be used to enhance focus/concentration on the front sight, leaving the bull out of focus. Even with a correctly prescribed lens, eyes change, illumination changes from range to range and day to day. Don't throw the baby out with the bath water.

Fred

[Mark Briggs]

I've seen SO many shooters using an iris in a fashion that was exactly opposite of how it should be used. This leads me to believe that few shooters understand very much about optics, the human eyeball, and pistol shooting. Certainly few understand the concept of "depth of field", which is the primary function of the iris, to alter depth of field.

Many people try to use the iris to limit light reflecting from a bright target. Man, is THAT the wrong thing to do!!!! If the target's that bright, use a filter, not an iris.

Now it's time for a confession... I have several pairs of shooting glasses, Knobloch and Varga's, and have an iris for each pair. The Varga iris is considerably larger when fully open than the Knobloch iris. After playing around a bit I decided to take the Knoblock iris off my "every day" shooting glasses and have been rewarded by a significant improvement in clarity of sight picture. It seems that reflections from the iris or some other yet-to-be-quantified force was causing my vision to blur about 3 seconds into the shot process. I'm glad to see that particular demon gone! And just as a sidebar note, I don't have this same problem with the Varga iris. I'm suspecting it's because the Varga opens up far wider than the Knoblock iris.

[jjgun]

Fairly new to international pistol so I'm still trying to work a number of things out. Didn't have these issues with the UltraDot :). I normally wear bifocals (Arghh) so I had a pair of glasses made with the non-shooting eye focused at distance and the shooting eye focused at the front sight. I can shoot Standard Pistol really well (50 ft) - B33 target provides lot's of contrast. It's blurry, but it's size provides a good picture. However, I seem to struggle with the smaller Air Pistol target. Maybe the different sights on the two guns contribute also?

Thanks to all for the helpful replies.

[jjgun]

Fairly new to international pistol so I'm still trying to work a number of things out. Didn't have these issues with the UltraDot :). I normally wear bifocals (Arghh) so I had a pair of glasses made with the non-shooting eye focused at distance and the shooting eye focused at the front sight. I can shoot Standard Pistol really well (50 ft) - B33 target provides lot's of contrast. It's blurry, but it's size provides a good picture. However, I seem to struggle with the smaller Air Pistol target. Maybe the different sights on the two guns contribute also?

Thanks to all for the helpful replies.

[RobStubbs]

Rob,
Why do you assume that use of an iris automatically leads to a sharpening of the bull and incorrect sight picture? Properly adjusted, an iris can be used to enhance focus/concentration on the front sight, leaving the bull out of focus. Even with a correctly prescribed lens, eyes change, illumination changes from range to range and day to day. Don't throw the baby out with the bath water.

Fred

Fred,
See the reply below your post.

A smaller aperture increases depth of field - that's basic physics, and that's what an iris is used for (except in a few specific circumstances). An iris cannot therefore increase focal clarity on for example the foresight without doing exactly the same for the target (and rearsight). As I said, if you want to alter focus onto the foresight then get a proper lens made. If the light is wrong then use a filter.

Rob.

[PETE S]

I wonder how many top competitors are using an iris? I think few if any.

I believe MR. Stubbs is quite correct that the better solution is to learn to focus on the front sight. You are having trouble because your focus is drifting to the target and not staying on the front sight. The iris may make it possible to see the front sight and everything esle a bit better, but the correct lens and truely learning to stay on the front sight is the better solution.

A similar problem can occur when shooting outdoors on a bright sunny. Everything appears in focus, the front sight the target etc. But are you really detecting slight misalignments in the sights because your focus is else where.

Every pistol shooter in the world will tell you they are looking at the front sight. Turns out that few of us actually do look at, focus on and have our attention on the sight alignment.

[Shooting Kiwi]

Just to muddy the waters further...

Because a small aperture increases depth of focus, the target can (will) appear better focussed, even when you are doing your best to focus on the front sight. This can be an almighty distraction, causing you to shift your optical and mental focus to the target. However, especially for us oldies, the increased sharpness of the bull can be a blessing, turning it from a huge, fuzzy blob, to something better defined that you can actually point at with some accuracy!

The iris also controls your head position, reducing yet another variable.

Do remember to put the sights and target centrally within the iris aperture: if off-centre, you can run into problems with diffraction from the edge of the iris.

I heartily second the advice to control dazzle. etc. by use of a filter, not the iris.

If it works for you, use it, otherwise junk it. I can't manage very well without one.

[somewhereinla]

A lot of AP shooters have used an iris sooner or later, but from what I have read, most stopped wearing it. I think a lot of people feel that being able to focus on both the target and the sight would be an advantage but actually most shooters find out that it can be quite the opposite...

[tenex]

When I shoot at a dark range (with bright target lights) I get a tremendous amount of glare off the sights and can't get a clear sight picture no matter what prescription lens I put in front, and I've tried a lot. The only thing that helps me is an iris. I currently wear a pair of Varga glasses with a +0.75 lens and an aperture over my regular distance glasses (they actually fit quite well) and simply adjust the aperture for the clearest sight picture.

If I could see the sights clearly without the aperture I'd chuck it, but right now it's the only thing that keeps me from putting a red dot on my air pistol (that, and those pesky rules).

Steve.

P.S. I was watching the AP finals from the World Cup and they shoot in a very bright ambient light level, unlike the dungeon like conditions of many indoor ranges.

[slinger]

OK, I will throw some more mud in this mess. I use a Clear Sight,,,,,,,,different from and iris for sure. It DOES allow me to focus on the front sight, and it DOES keep the target blurry. I can NOT shoot iron sights without this critter as I can not get a good focus. I have different + lenses for this, and find it takes a 3/4+ for me and a cloudy and dark day, VS. a 1/2+ on a clear and sunny day. I never could get used to being "behind" an iris,,,,,just my take.

[Fred Mannis]

OK, I will throw some more mud in this mess. I use a Clear Sight,,,,,,,,different from and iris for sure. It DOES allow me to focus on the front sight, and it DOES keep the target blurry. I can NOT shoot iron sights without this critter as I can not get a good focus. I have different + lenses for this, and find it takes a 3/4+ for me and a cloudy and dark day, VS. a 1/2+ on a clear and sunny day. I never could get used to being "behind" an iris,,,,,just my take.

An excellent point. Can't understand why some object to using an appropriate mix of lens, filter and iris diameter, but not to a lens and filter combination that is appropriate for a given pupil size/light level. I don't believe there is single proper lens prescription i.e one that will be optimum for any lighting condition.