> What are yours rules of thumb for F value setting in
> different situations?
Several months ago I did lens resolution tests. It contained
tests of various older Zuikos as well as the 14-54. Here is a
repeat of that post:
Using the USAF line-pair test chart, I photographed it using my
collection of lenses using the same chart-size (filling the
viewfinder). I had the chart taped to the side of my house in
direct sunlight and used every common F-stop from F4-F22 (if the
lens supported it). In a couple of instances, I did also do a
wide-open test.
I was a touch lazy in the summer heat and just used a monopod,
but the shutter speeds never dropped below 1/250, so I was
pretty safe. Aperture priority exposure mode. If I feel like
doing this again, I'll use a tripod. Also, I used JPEG HQ mode
with +2 sharpening. No halos visible. In comparative testing,
I've found an increase of about one line pair when shooting RAW.
So these measurements are relative to a best possible in JPEG HQ
mode.
First things first. The DZ 14-54 lens is as good if not better
than any of my prime lenses when it comes to sharpness and
contrast. Therefore, there really is no gain to shoot with the
prime lenses in any focal length the DZ covers. However,
distortion, and symmetry is a touch better with the old Zuikos.
There are other issues at play too, but for pure resolution, the
DZ 14-54 is outstandng. I'll get into specifics on the website
where I'll post samples of each focal length and aperture, but
I'm summarizing here with my comments.
A measurement of -1 LP means that it resolved one less line-pair
from the best image possible (in this test). As no lens or
setting exceeded my best possible, I believe I hit the AA filter
and process engine limits. -2 LP would be two line-pairs less.
For a point of comparison, the limit is the sixth "6" LP in my
test chart.
24/2.8 (multicoated blacknose) sn 2240XX
F4, -2 LP
F5.6, -1 LP
F8, 0 LP
F11, 0 LP
F16, -1 LP, reduced contrast
35/2.8 (singlecoated, silvernose) sn 1599XX
F4, -1 LP
F5.6, 0 LP
F8, 0 LP (nicest)
F11, 0 LP,
F16, -1 LP, reduced contrast
50/1.8 (silglecoated, silvernose) sn 2730XX
F1.8, -1 LP (reduced contrast)
F2.8, -2 LP
F4, 0 LP
F5.8, -1 LP (very close to F4, F8)
F8, 0 LP
F11, -1 LP (very close to F8, reduced contrast)
F16, -1 LP (reduced contrast)
50/3.5 (singlecoated, silvernose) sn 1254XX
F3.5, -1 LP (reduced contrast)
F5.6, 0 LP
F8, 0 LP
F11, 0 LP
F16, -1 LP (reduced contrast)
F22, -2 LP (reduced contrast)
100/2.8 (singlecoated, silvernose) sn 1306XX
F2.8, -1 LP (reduced contrast)
F4, -1 LP
F5.6, 0 LP
F8, 0 LP
F11, 0 LP
F16, -1 LP (reduced contrast)
F22, -1 LP (reduced contrast)
200/4 (singlecoated, silvernose) sn 1382XX
F4, -1 LP, (reduced contrast)
F5.6, -1 LP
F8, -1 LP (best)
F11, -1 LP, (best)
F16. -2 LP
F22, -2 LP (reduced contrast)
F32, -2 LP (need to reshoot, motion blur)
Now for some comparisons...
DZ 14-54 Zoom at 14mm
F2.8, 0 LP (reduced contrast)
F4, 0 LP
F5.6, 0 LP (best)
F8, 0 LP
F11, -1 LP
F16, -1 LP
F22, -2 LP (reduced contrast)
DZ 14-54 Zoom at 25mm
F4, -1 LP
F5.6, 0 LP (best)
F8, 0 LP
F11, -1 LP
F16, -2 LP
F22, -2 LP, (reduced contrast)
DZ 14-54 Zoom at 37mm
F4, -2 LP (surprisingly soft wide open--must be crossover FL)
F5.6, 0 LP
F8, 0 LP
F11, -1 LP
F16, -1 LP
F22, -2 LP (reduced contrast, soft)
DZ 14-54 Zoom at 54mm
F4, -1 LP (really close to 0 LP)
F5.6, -1 LP (really close to 0 LP)
F8, 0 LP
F11, -1 LP
F16, -1 LP
F22, -2 LP (reduced contrast)
The older prime lenses have a wider "sweet spot". The bokeh is
better and the general "feel" is a little nicer. This test
didn't compare any of that, just resolution.
As always: Your Mileage May Vary (YMMV). If you don't like my
tests, do you own.
AG
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