At 00:58 9/29/02, Ag-Schnozz wrote about the 100/2.8 :
Now that I've done the test, I'm still not sure how sharp it is.
All I am sure of is that I ran out of magnification. I know
there were discernable bars at least two steps smaller than what
were in the 35/2.8 images. Beyond that, I have no clue. F11 and
F16 yielded perfect sharpness AND greater contrast than the
other lenses. I'll have to use the grain magnifier under the
enlarger to figure out where it ends.
F8 experiences minimal resolution fall-off in the corners, but
F4 and 5.6 definitely showed where the sharpness wasn't.
Beautiful. Now I have confirmation on this lens. It really
does rock. It didn't matter that I went all the way down to
F16. It just got contrastier and contrastier and sharper and
sharper--so much for diffraction.
I'm not too surprised at f/16 not exhibiting any diffraction limiting on a
100mm lens. Diffraction limiting is typically more pronounced on shorter
lenses versus the longer ones:
aperture diameter = (focal length) / (aperture f-number)
It's why lens designers can use minimum apertures of f/22 and f/32 on the
longer lenses without introducing unacceptable degradation. Obviously this
is a broad generality and YMMV depending on specific lens length and design.
BTW #1:
I am happy about what you have discovered regarding your lenses (seems
better results than you had anticipated). Overall, the Zuiko's are a
marvelous lens system. The more I use mine (Schwarz-Schnozz), the more I
discover what I thought were weaker lenses is more due to my failings
(camera shake and careless focusing) than any failings in lens design.
BTW #2:
Just got back some Delta 3200 shot at EI 1600 indoors under available light
and processed push one. Nice, very nice. First roll looks a tad
contrastier than Kodak's TMax P3200 shot in the same manner in the same
venue with the same body and lens, but not by much. Also a tad less grainy
(TMax P3200 @ EI 1600 and push 1 is more like Tri-X @ ISO 400) and
mid-tones look decent in spite of being a notch contrastier. I need to try
some one of my rolls of Delta 400 at EI 1600 and push 2 for yet another
comparison.
-- John
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