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Support Equipment For PCP/HPA/CO2 and springers ,rams => Scopes And Optics Gate => Topic started by: Florida Grown on November 24, 2018, 03:45:13 PM
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ok....im gonna just probably look ignorant here but ....my understanding is exit pupil is image size exiting and relief is distance from eye to glass. is that basically correct? So I look at things a tad different than most normal folk as I am a degreed commercial photographer. I look at apertures, lens build quality/abberations in the glass and orientation( fast/slow). what I cannot grasp is how do exit AND relief play together and what numbers to look for, or rather how to decipher not just each number but both specs to judge a glass. in my head and I probably got this all wrong.... I want larger exit size and shorter relief????
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Hi Sterling,
The real key is getting your head in the same position for each shot. If the exit pupil is to small, if your head is just in a little bit different place you will not get a full image though your scope. The eye relief can get set by moving your scope forward or backwards on the gun. As you increase magnification, eye relief will shrink. I believe most people set there eye relief to far away and them have to mash their cheek into the stock to get a good sight picture.
A large exit pupil and longer eye relief just enables you to not be quite so precise when you put your head to the stock.
-Y
IMHO good turrets and reliable A/O range finding are much more important in choosing a scope.
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It's definitely better IMO to have a little larger eye relief. But like Yogi mentioned, setting your scope in the right position for proper eye relief is a good place to start.
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Look this should be simple as smashed taters...jesis!...simple...do we want large exit or larger range relief? Not complicate folks.
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Eye relief is the distance from the ocular lens at which you need to place your eye to see the image. A pistol scope will have a longer eye relief than a rifle scope.The exit pupil is approximately the objective diameter divided by the power setting of the scope. A smaller exit pupil size makes eye placement much more critical. I believe three mm is generally accepted as a minimum practical diameter but you can still use the scope with a smaller number.
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Exit pupil is the relative brightness of your optical system, or rather, the area of the exit pupil is a measure of the brightness. 10mm exit pupil is 4 times more light than a 5mm exit pupil. Depending on your eyesight, daylight viewing is generally fine at 3 mm and above, but at dusk/dawn that low light is much more problematic. Objective diameter divided by magnification is the maximum exit pupil you can get; internal "apertures" can reduce that, especially any field stops and internal lenses.
Eye relief is mostly a function of the eyepiece design. For more reading on that, you'll want to check out the amateur telescope maker (ATM) groups. For example:https://www.chuckhawks.com/common_eyepiece_designs.htm (https://www.chuckhawks.com/common_eyepiece_designs.htm) and another that will keep you busy for a while https://www.telescope-optics.net/ (https://www.telescope-optics.net/)
I haven't been able to find one eyepiece design summary I saw ages ago that expressed the eye relief as a fraction of the eyepiece focal length which varies with the different designs. I believe most rifles scopes are long focal length designs. The zoom and high power is achieved by the internal erection lenses assembly. Then there is the personal factor--I don't like looking through the Nikon Action as much as I liked the Orion Savannah binoculars, both 10x50.
Sometimes "eye relief" problems are actually other optical aberrations, e.g. kidney bean and curvature. (Put other lenses together with an eyepiece and other things can go wrong too.)
Of course, the wiki article might be useful, though sometimes you take them with a grain of salt: https://en.wikipedia.org/wiki/Eye_relief (https://en.wikipedia.org/wiki/Eye_relief)
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Ahhh, thank you for the replies and links. Just was frustrated and for some reason i had always put the two together in defining a lens characteristic. I've got much better grasp on it now. Again thank you.
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Look this should be simple as smashed taters...jesis!...simple...do we want large exit or larger range relief? Not complicate folks.
Yes it really is! ???
-Y