No, I don't think you did "hear" me. I was not disputing that the
problem exists at all. I certainly agree that the problem was well
demonstrated with the 200/4 and I specifically said that I would expect
to find more vibration problems at focal lengths above 135mm. My only
point is that the vibration problem is *not* readily evident in the
tests of lenses up to 135mm. And I'm not depending on memory. I
examined these tests in some detail just before posting my note. I was
surprised that I couldn't find the evidence since I expected the opposite.
Chuck Norcutt
Moose wrote:
> 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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