John Austin wrote:
>
> They would all be "correct". The purpose of the test was to determine the
> correct ASA/ISO setting to give neutral results with that body. Load a roll
> of your favorite slide film and take pictures of a familiar object. A Kodak
> or McBeth color chart would probably provide the most objective results, but
> is by no means a necessity. Vary each exposure by changing the ASA/ISO
> setting on the camera (yes, you could also just dial in + and - exposure
> compensation). Make sure you keep very accurate records as to which frame
> number was exposed at which ASA/ISO. When the film is developed, carefully
> check the slides to determine which one represents the object correctly.
> That is the ASA/ISO setting that you should always use for THAT particular
> film in THAT particular camera. The test will need to be repeated for each
> camera body you own. A pain, yes, but each body can vary. If you're fussy
> about correct exposure with slide film, it would seem to be a necessary test
> to perform. I don't have the book in front of me, but if I recall correctly,
> it was necessary for John Shaw to rate Velvia at 32, 40, 50, and 80,
> depending on which N*k*n F4 camera body he used. These four different
> settings would all produce exactly the same results. The differences were in
> the camera metering systems. As you pointed out, plus and minus 1/2 stop is
> acceptable accuracy from a repair standpoint. And I imagine that other
> repair persons might not be as meticulous as you are and the differences
> could be even greater. Testing will solve this whole problem.
>
Ideally the procedure should be done by switching same roll of film
between bodies to eliminate variations in film and processing. This way
only the bodies change.
At a minimum the test shall be performed with films from the same
batch and the films processed together.
Regards
Lars
--
Lars Haven <mailto:lhaven@xxxxxxxxxxxxx> aka <lhaven@xxxxxxxxxxxx>
"When writing about women, one must dip one's pen in a rainbow"
D. Diderot
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