Alan writes:
<< This is really perplexing. >>
LOL, that is an understatement.
Also consider this: Modern and Popular Photography tests probably
suffered from the same auto diaphragm mechanism vibrations the show up
in my OM-1(n) based tests! Two, Photodo isn't a film based test, so
their MTF results will show upper end performance that can't be matched
on many consumer films. By that, I mean that by the time an SQF grade of
A is reached in my testing, the resolution capability of the film itself
has been maxed out. I'm probably only seeing differences in contrast.
Only now that I have seen some results on improved Fujichrome 64T Type
II film, do I realize that our beloved Zuikos can still churn out more
detail. My A-, A and A+ grades are so telescoped together by film
limitations and project lens limitations that there is clearly a grade
above A *if* you use a fine grain black and white film or perhaps
Velvia. But it isn't me who is going to go there and discover which are
even better than we think. Who cares what a lens is capable of with
Technical Pan if we only shoot with Technical Pan once every five
years? That is why I picked a more mainstream film speed. I suspect
that the Fujichrome 64T Type I film I used in testing reproduces details
of a 100 speed slide film, excluding Provia F.
More food for thought: any lens test I did greater than 500mm picks up
too much shutter vibration to be meaningful. I can see smeared vertical
resolution chart lines, whereas the horizontal are distinct. Based on
some wild horse shoots I just got back, shooting a tripod mounted 600mm
in the 1/125 to 1/1000th sec. range and tripping the shutter while
holding the body (as Olympus recommended in their earliest SIFs) will
result in pictures that far exceed what the SQF grades would lead one to
predict. But the SQF testing of long lenses demanded speeds between 1/8
and 1/60. At those speeds it is almost impossible to dampen shutter
vibration. For one, you don't dare hold the camera and pick up arm
vibrations. Not even the use of two tripods worked for me.
Gary Reese
Las Vegas, NV
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