TargetTalk

I just received a Knobloch Iris Shutter.

http://www.champchoice.com/store/Main.a ... item=K2062

I have seen examples of shooters wearing it on both the inside (on the eye side) and on the outside.

Is there a preference or difference on how to wear the device?

Why did you buy it, and what do you expect it to do for you?

Ideally to reduce the amount of light to the eye and create a "darker" sight picture. This would help with contrast with the sights and target. I have a lens for my astigmatism and my eye prefers less light. I am finding my eye has trouble focusing with more light so I am attempting to create a consistent sight picture no matter what range I am on.

lyoke2 wrote: ↑Tue Jul 27, 2021 11:34 am I just received a Knobloch Iris Shutter.

http://www.champchoice.com/store/Main.a ... item=K2062

I have seen examples of shooters wearing it on both the inside (on the eye side) and on the outside.

Is there a preference or difference on how to wear the device?

I have Champion brand glasses, and the way the iris mounts is on a swinging arm held by the screw that clamps the lens in place. I've alawys used mine on the inside, and I think because of the curved front of the lens, it won't go in front.

It goes on the inside, centered on the lens. You CAN move the lens around until it is exactly between your eye and the bull and parallel to the bull.

The purpose of the rig is to give you a uniform pupil diameter, because your eyeball is somewhat irregular. It also changes with the light.

I hope like hell you're talking about iron sight use!

Thank you!

Yes, it is for air pistol.

A few related issues:
Just like cameras, a smaller aperture will give a greater "depth of field" - ie. a longer focus range and although you will still not be able to focus on the rear sight, front sight and target, it can get closer than when using a larger aperture. The trade off is a reduction in light to the eye which can reduce contrast between sights and target (which is what the questioner wanted) and it is not good for Rapid Fire Pistol where a larger aperture is beneficial for sight acquisition and recovery between targets - particularly in 4 second series.

I find that the big advantage of an aperture is to regulate my sighting under all conditions, sunny, overcast and indoor (some well lit and some not).

The use of a coloured lens will assist in the reduction of light to the eye. That way, you can use aperture setting for controlling the sight picture and not the control of light. Yellow is good for black/white contrast. Try other colours as well.

Whether the aperture is inside or outside the lens? Mine is outside for easy access to the aperture control lever but the fact that you have observed both means that the decision is probably personal, not necessarily technical.

Good luck with the testing.

I cannot remember the source right now but it was authoritative and said that the aperture should be fitted closer to the eye, i.e. on the inside of the shooting lens. If you use an aperture and a coloured filter, the aperture is better on the inside to allow the filter to clip on the outside. YMMV but on my Knobloch rig, I cannot fit a filter over the aperture.

Interestingly, a number of the Olympic shooters have them mounted on the outside of their lenses.

Bob

It depends on the lens distance to the eye.
If too close you brush your eyelash on the iris as you blink...not good.
Fit inside if possible and use the biggest opening to achieve the result.
Too small iris will give a really good picture but eye fatigue will kill
your overall match.

I have been working with the shutter for a few days now. The sight picture is a world different. I mounted it on the inside so I can put the lens centering device on the outside to check the lens without having to take the shutter on and off. I have found some inconsistencies in my head position now that I am using the shutter.

Always learning something new!

lyoke2 wrote: ↑Sat Jul 31, 2021 8:58 am I have found some inconsistencies in my head position now that I am using the shutter.

That’s interesting. I started using an iris to try to make sure my head position was not inconsistent.

Bob

when using an iris on shooting glasses, it must be centered.
For this you need this:
https://buinger.com/Gehmann-centerer