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Message: <blockquote data-quote="Chosun Juan" data-source="post: 3811438" data-attributes="member: 92780">Good point - we can consider the differences in 'true field' (or the even less relevant 'area' as Lee is fond of) and this does have some relevance when considering resurfacing fish, otters or whatever, and circling raptors (all linear width seperations), but it is the 'apparent' field that helps compare across magnifications.At 30m, I calculate the width of the true field as:10×42SF  = 3.6m8.5×42SV = 4m8×32SV   = 4.2m8×42SF   = 4.4m8×30EII   = 4.6meven though the apparent fields of these 5 bins are broadly similar (within ~5° of each other).If true field is of great importance to folks, get one of the old extra wide angle 7× (ER permitting, a 500ft@1000yd/167m@1km bin would give a width of view of 5m @30m distance), otherwise the sharpish to the edge(ish) field of the 8×SF provides some benefit, and the SV's (sharp to the edge) are only a smidgen behind.    :cat:Chosun   :gh:</blockquote>