CharlieBrown17 said:
Scopes with short eye relief typically have a tight eye box, especially if variable power. I am not sure how you have come to that conclusion as the "eye box" is essentially a margin of error within the position of eye relief. Most high powered scopes are built with an eye relief of roughly 3.5" which is considered a small value. Check-out the latest offerings from S&B, Nightforce, Leupold, etc. See below.
Scopes with long eye relief are typically useable in a much greater range of distances from the scope.Again, see below.
I agree at the end of the day it's personal preference but I've never heard bad eye relief refer to a longer eye relief. Remember, we're talking about the AR platform. Long eye relief is the devil. I could see how you'd want longer eye relief on a revolver or even a scout rifle platform, for sure.
Copied over from SH:Eye Relief: This is the specific distance behind the scope's ocular bell at which the target image and reticle can be seen in the scope's full field-of-view (FOV). A distance that is either too short or too long results in blurry edges around a FOV that is smaller than optimum. Eye relief is a listed value by all scope manufacturers.
Exit Pupil: This is the cylinder-shaped beam of light that exits the scope and contains the target image. The diameter of this cylinder varies in size depending on the size of the scope's objective lens, and the particular magnification setting. In order for a shooter to see the entire FOV offered by the scope, the shooter's eye must be; 1)at the correct eye relief distance, and 2) INSIDE the diameter of light defined by the exit pupil diameter. An eye position outside (or on the edge of) the exit pupil diameter results in a blacked-out or blurry image.
I like to think of the exit pupil as a "floating disk" behind the ocular bell. The shooter's eye must remain inside this "floating disk" to see the entire FOV. This is no easy chore when a scope's magnification increases, because the diameter of the "floating disk" can shrink significantly.
Exit pupil is also a listed value by all scope manufacturers, or can easily be calculated by dividing the scope's magnfication setting by the objective lens diameter
Eye Box:Eye box is defined as the amount of "allowable error" in a shooter's eye relief position, yet still offering a clear target image and full FOV. In other words, an optimum target image and full FOV despite a shooter's eye being slightly in front of, or slightly behind the optimium eye relief position.
Eye box is NOT a listed value by any scope manufacturer.