At 01:25 PM 1/25/2009, Mike wrote:
>I was under the impression that the metering with OM lenses should be
>reasonably accurate wide open.
>I would think the OM 5DII would have the program shift function that
>Moose has pointed out in the 5D which maintains the equivalent exposure.
Hi Mike,
Are you sure that Moose said that? (Or maybe I'm misunderstanding
what you're saying that he said.) Chuck Westfall addressed the
issues of using the 5D with stop down metering in his March 2006 Tech
Tips as quoted below.
"Your <http://www.digitaljournalist.org/issue0603/
http://www.digitaljournalist.org/issue0508/westfall.html>Tech Tip
discusses an exposure metering issue with non-EOS lenses and the 20D
... [I] was told that the 20D included a feature to compensate for
this problem. Can you tell me if the same problem is to be
experienced with other EOS bodies such as the 5D, 30D or Digital
Rebel XT/350D? I use and enjoy a 16mm Zenitar, microscope and bellows
lenses so I would consider this a serious problem worth avoiding.
All EOS cameras have one or more exposure compensation programs
built-in to handle focusing screen brightness issues with coupled
lenses, i.e., Canon EF lenses. As I tried to explain in the earlier
Tech Tips article, there can be no such compensation program with
non-coupled lenses, mainly because the camera has no way of knowing
what the working aperture is. Consequently, it becomes the user's
responsibility to apply exposure compensation as required based on
the particular shooting conditions involved. To repeat, none of the
EOS cameras, film or digital, have any special magic when it comes to
providing exposure compensation values with non-coupled lenses. The
best we can say is that standard focusing screens for the EOS-1 class
cameras are likely to require less exposure compensation than the
screens for other current EOS digital models, simply because the
standard screens for EOS-1 do not have as much of a brightening
effect as the non-interchangeable focusing screens for other models
like the 20D, etc. But even the standard focusing screens for the 1D
class cameras may require exposure compensation with non-coupled
lenses. For best results, we recommend making test shots with the
equipment you plan to use, at the working distances and apertures
that are appropriate for the results you are attempting to achieve."
And here are the links to the original and follow-up articles:
<http://www.digitaljournalist.org/issue0508/westfall.html>>
<http://www.digitaljournalist.org/issue0603/westfall.html>
Later,
Johnny
__________________________
Johnny Johnson
Cleveland, GA
mailto:jjohnso4@xxxxxxxxxxxxxx
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