On 8/29/2010 7:32 PM, Chuck Norcutt wrote:
> I'll repeat what I said once more. In reviewing most of Gary's tests through
> 135mm I could find no definitive support for improved results with
> mirror/aperture pre-fire over OM-1 mirror lockup. By that I mean results
> worse by one full letter grade or more. If you do find it it's likely that
> the test is of a different lens. In fact most tests are of different lenses
> and simply not comparable.
>
> This is tedious stuff and I haven't gone beyond 135mm where I'd expect to
> find more vibration related problems. But up to 135mm I just don't agree
> there's a real problem.
I 'heard' you before. I just don't agree. Skip from 135mm to the 200/4, where
he did a series of directly comparable
tests ("Differences are significant at the 1/3rd grade level") all with the
same lens.
I admit that beyond that I am going largely on memory, from when I pored over
those tests at great length and had a
couple of off-line exchanges with Gary. My recollection is that I concluded
that the preponderance of evidence over many
lenses and tests supported the existence of the vibration problem.
The severity is going to vary by lens model, tripod head and legs, possibly
camera model and possibly individual
camera/mount. The point for me is that I know about it and use technique that
minimizes it. If I over compensate for any
particular lens, body, aperture, shutter speed, etc., I lose nothing. If I
decide it doesn't exist, and it does, I lose
sharpness on some shots.
Personally, the last roll I shot in an OM-1 were all hand-held, whether free
hand or on a light tripod. Why not?
Moose
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