It seems like it has been commented on here before that large exit pupils can cause problems when one has eye astigmatism - but I can't find the thread. Am I remembering this correctly?
I have had trouble in the past with getting a sharp view in my right eye especially when testing bins with large exit pupils (particularly in low light conditions). Although I'm not certain, I suspect that I have mild astigmatism in that eye. I've begun to consider lower power bins with larger FOV, such as the 7x42s. This issue could be a deal-breaker. Any comments would be appreciated.
Thanks, APS
Same here.
The astigmatism in my left eye is more visible when looking through 7x42 than when using a 8x32.
Any time the exit pupil is small enough to limit the effective aperture of the eye-bino optical system you will reduce abberations in comparison to a larger aperture (just like stopping down a camera lens). But I can't imagine limiting my bino use to small exit pupil binos to accomplish this. Better just to wear glasses to correct the astigmatism. I have substantial enough astigmatism that I don't really have a choice (unless I'm willing to have substantially compromised visual acuity. With my glasses on, my acuity is about 20/12. If my correction is off enough that my vision deteriorates to the 20/20 standard for good vision, I am quite bothered.).
--AP