Jeff Conrad schrieb: > > Julian Loke wrote: > > > P.S. Obstructions are not the only cause for dark > > corners: there is also the cos^4 law > > And the cos^4 falloff on a 24 TS-E with 11 mm shift in the long direction > is about 2.6 steps (assuming a 58.6 mm image circle), which often is OK for > a sky but is undesirable in other situations. Since I'm not aware of a > center filter (radial ND grad) made for this lens, I'm not sure that much > can be done about the dark edges. >
The cos^4 law applies for conventional lens designs. Retrofocus designs can be somewhat better off in this respect. It's also not quite clear to me, under what kind of lighting and what object shape the cos^4 law applies. Probably flat light sources that emit light evenly in all directions? Anyway, most modern wide angle lenses with retrofocus do much better than the cos^4 law would imply. Thomas Bantel * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
