tenex
reality-based
I was about to ask a question about differences in field edges and width in classic vs flat-field designs, then found a good post about linear and angular distortion that's already answered it, and is worth calling attention to. (Thanks Henry.) link
For my purpose I'll just add on the obvious consequence for apparent FOV: classic designs can "stretch" it a bit at the edges, while flat designs "shrink" it and appear to have a bit less.
This subject has often confused me because it doesn't seem immediately obvious how binos with the same magnification and actual FOV can have different apparent ones, and because manufacturers use two different formulas for calculating FOV in degrees, and seldom even state AFOV.
For my purpose I'll just add on the obvious consequence for apparent FOV: classic designs can "stretch" it a bit at the edges, while flat designs "shrink" it and appear to have a bit less.
This subject has often confused me because it doesn't seem immediately obvious how binos with the same magnification and actual FOV can have different apparent ones, and because manufacturers use two different formulas for calculating FOV in degrees, and seldom even state AFOV.