Exit Pupil and Scope Eyebox question

[Frank Dux]

Does exit pupil tell me how finicky a scope’s eyebox is? I have very little experience with scopes. Currently have a Nikon Monarch 3-12x42. This scope has an extremely forgiving eyebox. Looked it up and the exit pupil is pretty on the higher end, 3.5-14mm. I see some scopes that are similar in size but list smaller eye relief. Take for instance the 2.5-15x42 Trijicon Credo. 2.8-10.7mm. So at 2.5x it’s 2.8 where at 3x the Nikon has 3.5mm. Just curious if the exit pupil values tell me what I think they are, which is more exit pupil means an easier scope to get behind.

 

[schweinstein]

My understanding is exit pupil as a lot to do with it but its not the only factor. I had POS Bushnell scope once with TERRIBLE eye relief despite having decent exit pupil. The internals in that thing were junk. Despite what the math said about exit pupil.

 

[whoami-72]

From what I understand, your eye ball pupil is roughly around 2mm during bright daylight. Therefore, if the scope pupil is 3.5 mm then your eye can float inside and makes it feel like it has a longer eye box because its limited longitudinally by the scope "shadow" itself. However, the side to side movement is directly dependent upon the eye pupil being smaller. Long story short, I think you nailed it.