Eye Box

[Texas Solo]

My current scope has a small exit pupil. I think around 78. My new scope on order will have 82.
How much of a difference is this?

Currently, I have to keep my eye perfectly centered or the sight picture gets wonky.

 

[Krogen]

Please clarify . . . . 78 or 82 what? Exit pupils are typically in the 2 mm to 4 mm range.

 

[Texas Solo]

.087mm on golden eagle
.094mm on March
Both at 60x

 

[Texas Solo]

Anyone know?

 

[shoot4fun]

I'm not an optics guru by any means and don't claim to be. Calculating exit pupil of a rifle scope is fairly simple by formula so the GE scope has an approximate .86 exit pupil the formula shows a 60X magnification with a 56mm objective will be approximately .93, at least in a perfect world, the .93 will be brighter than the .86. I believe coatings play a very big role in what is referred to as "light gathering" and the latest versions of March scopes tend to have quality glass and coatings. The GE, IMO (and I am a huge Vortex fan), has lesser glass than the GE scopes I have been able to look through and does exhibit a degree of "darkness no matter how perfectly your eye is placed..
Now, I don't think the exit pupil calculation has anything to do with "eye-box". Don't believe me?
Having had many years experience with scopes of all types I find the scope's mounted height to have the biggest single factor in how critical that part of it is. If a scope is mounted too low or too high the shooter's head placement is likely the cause of not being able to see thru the scope instead of the scope itself.
I'm sure someone far more qualified than I am will come tell you how wrong I am butt, at least in my case, when I am not properly behind a scope (can't see the reticle) moving my head up or down will fix it no matter how much closer or farther away my head is from the ocular lens.

 

[Texas Solo]

I'm not an optics guru by any means and don't claim to be. Calculating exit pupil of a rifle scope is fairly simple by formula so the GE scope has an approximate .86 exit pupil the formula shows a 60X magnification with a 56mm objective will be approximately .93, at least in a perfect world, the .93 will be brighter than the .86. I believe coatings play a very big role in what is referred to as "light gathering" and the latest versions of March scopes tend to have quality glass and coatings. The GE, IMO (and I am a huge Vortex fan), has lesser glass than the GE scopes I have been able to look through and does exhibit a degree of "darkness no matter how perfectly your eye is placed..
Now, I don't think the exit pupil calculation has anything to do with "eye-box". Don't believe me?
Having had many years experience with scopes of all types I find the scope's mounted height to have the biggest single factor in how critical that part of it is. If a scope is mounted too low or too high the shooter's head placement is likely the cause of not being able to see thru the scope instead of the scope itself.
I'm sure someone far more qualified than I am will come tell you how wrong I am butt, at least in my case, when I am not properly behind a scope (can't see the reticle) moving my head up or down will fix it no matter how much closer or farther away my head is from the ocular lens.

"the scope's mounted height to have the biggest single factor in how critical that part of it is. If a scope is mounted too low or too high the shooter's head placement is likely the cause of not being able to see thru the scope instead of the scope itself."

Very true. But with an adjustable cheek riser that issue doesn't exist.

 

[shoot4fun]

"the scope's mounted height to have the biggest single factor in how critical that part of it is. If a scope is mounted too low or too high the shooter's head placement is likely the cause of not being able to see thru the scope instead of the scope itself."

Very true. But with an adjustable cheek riser that issue doesn't exist.

I own quite a few stocks with adjustable cheek risers. Scope height can still be an issue.
My point is exit pupil and eye box are not the same thing. Also, we are conditioned to say a scope "gathers light" when it actually has no ability to gather anything. The larger the objective and the better the coatings will allow a scope to pass more available light into and through the scope.
I always want my scopes mounted as close to the barrel as possible. Prone position is only for when I accidentally fall down these days but being prone is different, regardless of cheek riser or not and, for me at least, a scope has to be mounted slightly higher to align better with the (likely) excessive cheek pressure I put on the stock when prone (just bad habits AND OLD AGE).

 

[Dgd6mm]

It's kinda like setting a peep sight on a bow.
Close eyes, get your anchor points, open eyes. Adjust peep up or down until you're looking straight through it.
On a rifle I guess you can raise or lower your cheek weld.