> From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
>
> You've shown these before but I hadn't previously noticed that (except
> for the Vivitar f/8) the results could be interpreted as Zuiko is the
> winner or else lens speed is the winner. At f/8 the Zuiko is 2/3 stop
> faster than the Bausch & Lomb and a full stop faster than the
> Celestron.
> Can you be certain that the faster shutter speed presumably used with
> the Zuiko is not the cause of the sharper image (of live birds swaying
> in a treetop)?
Good question.
If you click on any of the thumbs, you get the EXIF data. None of them
were particularly slow, the slowest being 1/60th, I think. All were on
a tripod, and I took some trouble to avoid vibration and camera shake.
The sort of artifacts shown in the crop count against subject motion
-- there's CA going on, and no apparent linear blur, as one might
expect if a sudden wind gust moved things.
Note also that the f8 Zuiko Reflex blows away the f8 Vivitar, and that
the non-mirror Zuikos come out on top even when (especially when)
stopped down, which if subject/camera motion were an issue, it would
surely show up then. But the Zuiko 600 at f11 (1/80th of a second)
still handily bested the slower mirrors at similar shutter speeds.
Since it wasn't such a carefully controlled situation, subject motion
and shutter speed can't be ruled out, but given the EXIF data, it
seems unlikely to be a huge detractor from image quality in these cases.
There may also be other things going on, as well. I was hugely
disappointed in the Tamron 300/2.8, which seems to do fine on OM film
bodies.
:::: He who joyfully marches to music in rank and file has already
earned my contempt. He has been given a large brain by mistake, since
for him the spinal cord would fully suffice. -- Albert Einstein
:::: Jan Steinman <http://www.Bytesmiths.com/Item/99-6313-16>
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