keith_w wrote:
> After I spent a good bit of time looking over Gary's site, trying to absorb
> as
> much of it as possible, all i was left with was shaking my head, and
> realizing
> that "lens tests" are only as good as the paper they're written on, and at
> that time of day! :-(
>
> I'd find a lens that performed exceptionally well on, say, an OM-2. Then I
> checked the performance on an OM-1. Deteriorated in an instant! Awful
> performance, just by changing lens serial numbers, or camera bodies, or
> locking up a mirror ~ or NOT locking up the mirror!
>
I think you are giving up too easily. Gary only tested using three basic
body designs. Early tests were done on the OM-1, always with the mirror
up, unless he did some comparison test with and without.
Then he tried one of the newer design bodies which allow both aperture
and mirror pre-fire and found it made a significant difference, so he
started testing, and doing a few retests, using OM-2s and OM-4 bodies.
It doesn't matter which, as the significant mechanism is the same.
As he refined his work, he found that some lenses in a particular
size/weight range, mostly mid to longish teles, produced poorer results
at certain shutter speeds than might be expected. So he tried out
various things like lens supports, and found that vibration, not the
intrinsic optical resolution, was causing these problems. Although Gary
didn't test them, there are other ways to combat this problem, like the
hand technique recommended in the eSIF or the use of a beanbag on body
and lens. By calling attention to and documenting this problem, Gary did
a huge service to those of us who use these lenses.Without his aid, many
more fuzzy pics would have been made with these lenses sitting on
tripods and being fired with cable releases, assuming that would take
care of camera shake.
He also tried a few lenses with the OM2000, which also has
aperture/mirror pre-fire, but a vertical travel metal shutter, as
opposed to the horizontal travel cloth shutter of the others. Didn't
look to me like it made a significant difference.
Although they don't tell the whole story every time, these tests have
been a great resource for me. It's a lot easier if you are only focusing
on one or two focal lengths at a time. And some of the tests, like
seeing what a visually good, but optically flawed, filter can do to our
pics, are unique in my experience.
> In other words, the results of any given test are good under those specific
> conditions ONLY. Put the same lens on YOUR camera, and all bets are off.
> Might be just fine for you, or bear no resemblance to anyone else's testing
> results.
>
Gary was very aware of all this and tried as far as possible to make his
tests at least internally consistent, always using the same film and
test target. His tests are a unique and quite useful resource for
Zuikoholics. No other brand has anything even close.
> Finding the "truth" about lens performance is a study in frustration... <wry
> smile>
>
One truth is that an awful lot of lenses that test somewhat differently
will take great pics in practice. I do most of my photography hand held,
enlarge few images beyond 8x10 and so am not likely to see the
difference between a B and an A most of the time.
If you have further questions about particular lenses, try asking here.
Moose
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