Originally posted by: ElFenix
viewfinder size is easy. (size != brightness, btw. pentamirrors aren't as bright as pentaprisms, but unless you've got one up to one eye and the other up to the other, i don't know if anyone could tell)
sony sensor size: 23.6 x 15.8 mm
area = 372.88
viewfinder coverage: 95%
372.88 * .95 = 354.236
magnification: .88
354.236 * .88 * .88 = 274.320 sq mm viewfinder area (nearly the size of the 40D's at 289)(hmmm dpreview has the wrong sensor size for the 40D)
for the Rebel XS the viewfinder = 204.79 (which is bigger than the A300/A350 at 193.98)
Great -- thanks. That makes more sense to me.
I wonder if the mirrors themselves differ in brightness between manufacturers based on materials, coatings, or construction techniques? I imagine they do -- perhaps some objective measurement could be devised to accurately compare two VFs. A light meter attached to the VF with an open mount and a constant light source?