Edisonian approach Schnozz writes:
" Moose mentioned something about lenses. I've spouted off on this
before, so I won't reopen that wormy can, but will say thay my
PanaLeica lens is one of those lenses which definitely produces a
greater USABLE DoF than other lenses at the same focal length and
aperture. I know full well what the numbers say, but side-by-side
images tell a different story.
AG
Not sure the can is that wormy. Have seen one example of different
apparent DOF with two lenses at same aperture on same shot on FM that
was a very small sample size (n=1) but looked real. (One I think was
a zoom and other experimental design problems, but still)
Ideal lenses are used to construct the tables/calculators and do not
consider colors, aberrations, diffraction. The CoC is a disk of
even brightness. The distribution of brightness, however, is usually
uneven. Some modest vignetting (often fixed by lens/cam cpu)
can effect the effect pupil size and inc dof at the edges. (Is this
more imp't in MFT format?) Aberrations affect the type and relative
degree of blurriness in front of and behind the focal plane. Color
effects--- haven't seen much data on that either??
To quote Nasse " The usual tables and calculators therefore provide
for some useful tools for practice, but they should not be taken too
seriously."
So, I'll take AG's observations at face value, unless proven otherwise.
(see article by Nasse at Zeiss) http://tinyurl.com/yykxrhd
Perhaps this will waken the long lost Dr. Focus out of his slumber.
A believer in Not all lens fuzzy is created equal, Mike
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