Hi All,
I read with great interest these last few days on the "perceived" quality of
zoom lenses. I am sure, most on this list knows I am very fond of my beloved
85-250 f 5. It always stays attached to a body and used a great deal. I
bought it new in the late 1980s. I have always felt, that if I did my part
with proper technique, the lens would produce slides on par with the
corresponding primes. But, I had no personal evaluation to base this on.
So here are the results of my first test.
Setup: 2 slides shot with each lens at same settings: 4T; Velvia; Heavy
tripod; Mountain scenic; Sunny 16 & Bracket = f11 & +1 @ f 8, Self Timer so
mirror locked up.
Evaluation Methods:
1. Light Table with Peak 4X & 10X loupes
2. Scanned Nikon Coolsan II at 6.33 x 9.5 inches, 204.63 pixels / inch; file
size = 7.21 MB.
3) Printed with Epson Photo on Epson glossy photo paper.
4) Projected on quality screen aprox 2 ft. x 3 ft.
Results:
I will admit I am somewhat confused with the terminology used to describe lens
and picture quality and I think one persons evaluation might differ from
another. So I though it was best to have my wife and a visiting brother-in-
law to also evaluate the 4 slides. They did not know until later that I had
used 2 different lenses and what I was trying to do.
I think it is best to describe the results, so you - all can make your own
conclusion.
1. Light table - I studied all 4 slides for nearly an hour with both the 4x &
10x loupes. I COULD NOT honestly say one was overall sharper than another.
Only with the 10x loupe and focusing on a very small road sign (yellow one
with the wiggly arrow) about a mile away could I even see any difference. The
black arrow was sharper with the 85 f2, but not by much and this sign was in
the far lower corner of the frame.
There was a slight color difference; the zoom had a little more greenish tent
to the brown hill side areas. Whereas the 85 f2 gave a lighter brown cast.
MY WIFE: In about 5 minutes she said this one. (The 85 f2 with + one
exposure.) WHY? I ask. "It's just overall sharper than the rest."
BROTHER-IN-LAW: Without knowing what I was up to, sat down and in about 10
minutes said "this one" (85-250 Zoom at sunny 16 exp.) WHY? I ask. "It's
just sharper, look at the trees on the hill side"
At dinner, I told them what I was trying to conclude. Is the zoom as good as
a prime? So the sister / brother debate stared. My wife, "see there,
everyone knows primes are better than zooms, so I am right!" Brother "NO! You
didn't look at the details in the trees" Obviously a stalemate.
Last night, I spent about 3 hours, scanning, printing, and projecting back and
forth 50+ times. I even magnified the little sign to 300% to where the pixels
were taking over and yes, at 300% you could see some advantage with the 85 f2.
My conclusion: Well, I think the 85 f2 may be a touch sharper. If I were
going to print 11" x 14"'s, I MIGHT see a difference @ 8x10" I don't think so.
Bottom line, I plan to continue using my 85-250 zoom, knowing I will get good
sharp slides if I do my part.
Buddy Walters
Ps. I took the printed pictures (with identification covered up) to the den
and ask my wife which was best?
2 minutes later, this one! Which is it, the zoom or the prime?
Answer: THE ZOOM. B.S.!! she said.
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