Well you didn't list a 135mmm and standard portrait lens is more like 85mm
for 35.
that's an unusual take. I do not own nor many I know own an 85mm, it's too
short. However, 100-135mm amazingly covers the same angle as the angle of
concentration - 15 degrees-ish
Normal lens for a given format is determined by the hypot of
the format. Thats how a normal lens is determined. It has nothing to
do
with how we see. Its why if you look around you will find a lot of 40mm
and 45 and 43(bingo) lenses. It has to do with how light travels
through
optics. I have no clue why you are talking about what a normal lens is.
a 50
convention again. Have you ever actually measured the angle of view of 50mm
lenses? Funny thing is I have not met a single one that IS 50mm, they're
all around 43mm - but convention within lens makers saw them marked as 50mm
as it was presumably easier for folks to think of them in a nice round
number. I tested a lot of lenses in my days to see how far they deviated
from the marked focal lengths. Not hard to do..
with all things being equal will be sharper then a 200mm with will
require corrections for chromatic and other aberrations. when I was
shooting my Book on Vetrans my lens was a 460mm on 8x10 or about the same
as 85mm on 35. None of which matters at all because you are talking pure
asthetic now and nothing of human perception has it relates to awareness.
MIght I suggest the TV show brain games.
chromatic aberrations are a function of any lens, irrespective of focal
length as light is just argumementative and separates into all those
annoyingly different wavelengths as it slows when traveling through
different media. All designs have to compensate in one way or another. Oh,
and I've even seen barrel distortion ina 50mm lens ;)
I have a nice Bausch & Lomb 508 telephoto (for real!) I use for portraits on
my 8x10. It makes the bellows manageable ..
Funny thing, I was talking to a physicist and he really didn't comprehend
that's what is happening when light is diffracted! He carried on about how
the speed of light was constant and I must clearly misunderstand. I tried
to explain no, 'speed of light' is *used* as a constant (it's actually a
definition), but light can definately be slowed.. I think they actually
managed to get it down to zero, but the most frequently quoted slowed speed
is around 38 mph. Imagine what sort of wide angle lens you could make with
whatever media they used for that experiment!
