Re: cos^4 law

From: BC (brianc1959_at_aol.com)
Date: 01/14/05 

Date: 14 Jan 2005 13:54:01 -0800

I've always had a problem with using the image space chief ray angle as
the cosine argument (as opposed to the field angle) since it has to be
determined by ray tracing and is so easily complicated by exit pupil
spherical aberration. However, if you want to use that definition then
you're correct. Of course, by that definition even fisheye lenses will
obey the cos^4 rule so long as there is no exit pupil aberration, and a
number of textbooks will have to be revised!
Brian
www.caldwellphotographic.com