Scopes- Eye Position Forgiveness

Departed402 · August 11, 2013, 02:39 PM

Help me out. I'm looking for a scope with what I am going to call "eye position forgiveness." In the simplest terms I can put it I am looking for a scope where you can see the full view of the scope, and the position of your eye has plenty of room for movement side-to-side and forward and back without seeing the edges. If my understanding is correct this has to do with both "eye relief" and "exit pupil."

I hate to make a "school me" thread, but I don't understand what variables of a scope (lens size, etc.) affect these things. Please fill me in, or point me in the direction of a good website.

allaroundhunter · August 11, 2013, 02:46 PM

Simply look at a scope's eye relief. That is all you need to be concerned with. That is the (approximate) distance that your eye has to be from the ocular lens to get a full field of view. What you don't want is to e moving your eye very much side-side. This can introduce parallax and will result in a missed shot. A consistent cheek weld (and thereby eye placement) from shot to shot is what creates accuracy.

What gun are you mounting the scope on?

Doyle · August 11, 2013, 03:38 PM

I'm sensitive to eye relief in my scopes too. I cannot stand to have a short eye relief scope that causes me to crane my neck. Therefore, most of my rifles wear Leupold scopes.

Brian Pfleuger · August 11, 2013, 04:44 PM

Eye relief has nothing directly to do with (or it's not the first thing, at least) how much you can move your head "without seeing the edges".

That's exit pupil.

The human eye can dilate from about 2mm to about 7mm. An exit pupil that is larger than your eye can dilate (or is dilated) gives you "wiggle room".

A fixed power scope will have a set exit pupil size because exit pupil is calculated by dividing the lens size by the magnification. A 32mm objective lens on a 4 power scope gives you an 8mm exit pupil.

You'll notice that 8mm is (probably) larger than your eye can dilate. That means you've go an extra 1mm or so of "wiggle room".

Looking at the calculation, you can see that larger objective lens and lower magnification both increase the exit pupil while smaller lenses and higher magnification reduce it.

Eye relief comes into it in the sense that the longer the eye relief, the more forgiveness there is in exact placement front to back for a good image. Technically, any time your head is not at the exact correct eye relief for the scope, the image will be slightly out of focus. However, if the scope has a 76mm (3") eye relief and you're out of position by 3mm, the "out of focus" would be twice as bad as being 3mm out of position on a scope with 150mm (6") eye relief.

jmr40 · August 13, 2013, 08:02 PM

Simple answer, buy a Leupold. Most forgiving scopes I've ever used as far as eye position. I'm not concerned about hitting my eye with the scope, but being able to find the target in the scope quickly. Talk about exit pupil all you want, it is the scopes magnification and eye relief that matter. As a rule Leupold has the most eye relief of any scope maker in comparable scopes. You will find a few exceptions in specialized scopes, but those are few and far between.

ripnbst · August 13, 2013, 10:21 PM

I've got a Zeiss Conquest that has a straight up insane eye box. It's the best I've ever experienced.

August 11, 2013, 02:39 PM	#1
Departed402 Senior Member Join Date: September 25, 2009 Location: Midwest Posts: 884	Scopes- Eye Position Forgiveness Help me out. I'm looking for a scope with what I am going to call "eye position forgiveness." In the simplest terms I can put it I am looking for a scope where you can see the full view of the scope, and the position of your eye has plenty of room for movement side-to-side and forward and back without seeing the edges. If my understanding is correct this has to do with both "eye relief" and "exit pupil." I hate to make a "school me" thread, but I don't understand what variables of a scope (lens size, etc.) affect these things. Please fill me in, or point me in the direction of a good website. __________________ Slow is Smooth. Smooth is Fast.

August 11, 2013, 02:46 PM	#2
allaroundhunter Senior Member Join Date: May 6, 2012 Location: Southeast Texas Posts: 1,670	Scopes- Eye Position Forgiveness Simply look at a scope's eye relief. That is all you need to be concerned with. That is the (approximate) distance that your eye has to be from the ocular lens to get a full field of view. What you don't want is to e moving your eye very much side-side. This can introduce parallax and will result in a missed shot. A consistent cheek weld (and thereby eye placement) from shot to shot is what creates accuracy. What gun are you mounting the scope on?

August 11, 2013, 04:44 PM	#4
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	Eye relief has nothing directly to do with (or it's not the first thing, at least) how much you can move your head "without seeing the edges". That's exit pupil. The human eye can dilate from about 2mm to about 7mm. An exit pupil that is larger than your eye can dilate (or is dilated) gives you "wiggle room". A fixed power scope will have a set exit pupil size because exit pupil is calculated by dividing the lens size by the magnification. A 32mm objective lens on a 4 power scope gives you an 8mm exit pupil. You'll notice that 8mm is (probably) larger than your eye can dilate. That means you've go an extra 1mm or so of "wiggle room". Looking at the calculation, you can see that larger objective lens and lower magnification both increase the exit pupil while smaller lenses and higher magnification reduce it. Eye relief comes into it in the sense that the longer the eye relief, the more forgiveness there is in exact placement front to back for a good image. Technically, any time your head is not at the exact correct eye relief for the scope, the image will be slightly out of focus. However, if the scope has a 76mm (3") eye relief and you're out of position by 3mm, the "out of focus" would be twice as bad as being 3mm out of position on a scope with 150mm (6") eye relief. __________________ Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley Last edited by Brian Pfleuger; August 11, 2013 at 04:54 PM.

August 13, 2013, 10:21 PM	#6
ripnbst Senior Member Join Date: November 24, 2010 Location: Spring, TX Posts: 1,552	Scopes- Eye Position Forgiveness I've got a Zeiss Conquest that has a straight up insane eye box. It's the best I've ever experienced.

August 11, 2013, 03:38 PM	#3
Doyle Senior Member Join Date: June 20, 2007 Location: Rainbow City, Alabama Posts: 7,167	I'm sensitive to eye relief in my scopes too. I cannot stand to have a short eye relief scope that causes me to crane my neck. Therefore, most of my rifles wear Leupold scopes.

August 13, 2013, 08:02 PM	#5
jmr40 Senior Member Join Date: June 15, 2008 Location: Georgia Posts: 10,808	Simple answer, buy a Leupold. Most forgiving scopes I've ever used as far as eye position. I'm not concerned about hitting my eye with the scope, but being able to find the target in the scope quickly. Talk about exit pupil all you want, it is the scopes magnification and eye relief that matter. As a rule Leupold has the most eye relief of any scope maker in comparable scopes. You will find a few exceptions in specialized scopes, but those are few and far between.