Hi!
I'm shooting 10m air rifle. Today, my coach passed me his anschutz rear iris (he calls it diopter) because I was complaining about the glare coming from the target cards when I take aim. It comes with a variable iris, colour filters and two polarization filters, so it's a lot of stuff to tinker with.
I tried some really random adjustments today and managed to get a sight picture that is less glaring, but definitely far from ideal. I may be able to get a good adjustment after a few more hours of tinkering on my next training, but I know I won't have the luxury of time when I go to other ranges for competitions, where the lighting conditions are different.
Can anyone share some experience on how to adjust these components correctly and decisively? All advice will be greatly appreciated!
How to Adjust Rear Iris? (size, colour, polarization etc)
Moderators: pilkguns, Marcus, m1963, David Levene, Spencer
I personally don't use anything but an adjustable iris for air rifle, or any indoor shooting. But here's a breakdown of what everything does:
Iris - Opens and closes the rear aperture. The primary function is to make the front sight and bull look crisp and clear. Opening it up has the side effect of letting more light in and closing it down lets in less.
Polarizer - For now, just use the on and off part of it. You likely have an adjustable one, but for indoor, I doubt you'll need it. It reduces glare with the side effect of reducing the amount of light making it to your eye resulting in a darker sight picture. Polarizers make the light making it to your eye in phase reducing the amount of interference which also makes the sight picture have sharper edges in bright light (crisp circle rather than slightly blurry edges).
Color Filters - For indoor, yellow is the most commonly used color if one is used. It helps with the contrast between the bull, front sight, and edges of the rear sight.
My suggestion would be to put a polarizer on and set the rear iris size such that you get a good crisp image. This would make my sight picture too dark for my liking. If that is that case, try the yellow filter. It will block out less light than the polarizer.
Iris - Opens and closes the rear aperture. The primary function is to make the front sight and bull look crisp and clear. Opening it up has the side effect of letting more light in and closing it down lets in less.
Polarizer - For now, just use the on and off part of it. You likely have an adjustable one, but for indoor, I doubt you'll need it. It reduces glare with the side effect of reducing the amount of light making it to your eye resulting in a darker sight picture. Polarizers make the light making it to your eye in phase reducing the amount of interference which also makes the sight picture have sharper edges in bright light (crisp circle rather than slightly blurry edges).
Color Filters - For indoor, yellow is the most commonly used color if one is used. It helps with the contrast between the bull, front sight, and edges of the rear sight.
My suggestion would be to put a polarizer on and set the rear iris size such that you get a good crisp image. This would make my sight picture too dark for my liking. If that is that case, try the yellow filter. It will block out less light than the polarizer.
rule of thumb to work with, open the iris up till it's brightest, then turn it down and stop when you notice the target dimming.
it's a rule of thumb because if you make it dimmer you get more of the target in focus against the foresight, but the dimness strains the eyes... to large and the fuzzyness and brightness can also have negative effects.
the polarizer only really has benefit outdoors to reduce glare... indoors the light source isn't of the right type to make it beneficial.... i'd leave it off.
yellow vs black is the best contrast for the eye, but if your using a filter this will dim the image, so it might induce strain.
start off as per the rule of thumb and play with variation, but make a note of the settings so you know where to return to.
it's a rule of thumb because if you make it dimmer you get more of the target in focus against the foresight, but the dimness strains the eyes... to large and the fuzzyness and brightness can also have negative effects.
the polarizer only really has benefit outdoors to reduce glare... indoors the light source isn't of the right type to make it beneficial.... i'd leave it off.
yellow vs black is the best contrast for the eye, but if your using a filter this will dim the image, so it might induce strain.
start off as per the rule of thumb and play with variation, but make a note of the settings so you know where to return to.
The iris should be pretty much set at about 1mm and left (maybe try from 0.8 - 1.2 if you must). Too much tinkering can muck things about and make things worse. Remember the target should not be in focus so don't try and get it to be - it will go against you, and shutting down the iris to make it sharper induces eye strain as already mentioned. Filters and polarisers have their place, but again be wary of cutting light such that it becomes a struggle.robf wrote:rule of thumb to work with, open the iris up till it's brightest, then turn it down and stop when you notice the target dimming.
it's a rule of thumb because if you make it dimmer you get more of the target in focus against the foresight, but the dimness strains the eyes... to large and the fuzzyness and brightness can also have negative effects.
Rob.
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Anschutz
Then whats the point in having a adjustable iris,lets just stick to the one that comes with the sight 1.1mm in most sights. Our eyes are different and react differently to light levels, turn the iris to you find what's best for you, but as above don't over do it.RobStubbs wrote:The iris should be pretty much set at about 1mm and left (maybe try from 0.8 - 1.2 if you must). Too much tinkering can muck things about and make things worse. Remember the target should not be in focus so don't try and get it to be - it will go against you, and shutting down the iris to make it sharper induces eye strain as already mentioned. Filters and polarisers have their place, but again be wary of cutting light such that it becomes a struggle.robf wrote:rule of thumb to work with, open the iris up till it's brightest, then turn it down and stop when you notice the target dimming.
it's a rule of thumb because if you make it dimmer you get more of the target in focus against the foresight, but the dimness strains the eyes... to large and the fuzzyness and brightness can also have negative effects.
Rob.
It's true most of them adjust way more than most people need. I've never been much below 0.9mm or much above 1.0. But there is a HUGE difference in what those two look like depending on the day. If it's overcast and raining, I can't see at .9, and on a clear sunny day, I get too much glare at anything bigger than .9 with a polarizer. For a beginner, the differences will be more for comfort than performance so long as there isn't something extremely out of whack.
The point of adjustable irisis is that we as shooters like gadgets and search for the elusive panacea that will make us all into great shooters. Whilst perhaps I was over-egging the point, more shooters mess things up without realising and eventually go back to what originally worked. If adjustable irises only went from 0.8 - 1.2 then I'd recommend them, but they cover far to large a range. That encourages those that know no better to try the extremes and ultimately waste time doing so or worse, shoot with a bad setup.Anschutz wrote:Then whats the point in having a adjustable iris,lets just stick to the one that comes with the sight 1.1mm in most sights. Our eyes are different and react differently to light levels, turn the iris to you find what's best for you, but as above don't over do it.RobStubbs wrote:The iris should be pretty much set at about 1mm and left (maybe try from 0.8 - 1.2 if you must). Too much tinkering can muck things about and make things worse. Remember the target should not be in focus so don't try and get it to be - it will go against you, and shutting down the iris to make it sharper induces eye strain as already mentioned. Filters and polarisers have their place, but again be wary of cutting light such that it becomes a struggle.robf wrote:rule of thumb to work with, open the iris up till it's brightest, then turn it down and stop when you notice the target dimming.
it's a rule of thumb because if you make it dimmer you get more of the target in focus against the foresight, but the dimness strains the eyes... to large and the fuzzyness and brightness can also have negative effects.
Rob.
Just to illustrate, on a coaching course I attended we had about 1/2 a dozen shooters with adjustable irises. That had all settled on between 1.0 and 1.2 as I recall, and then left them alone for all their shooting.
The advise is also not to change the iris size with light conditions rather to use filters. You may well however need to adjust the foresight element size depending on conditions.
Rob.