P3D Re: More Medical Stereo Photo Questions

[aifxtony@xxxxxxx (Tony Alderson)]

>I will be photographing (stereo) a surgical procedure in a few days using
>either my TDC or Realist camera.

If this is a TDC Vivid, that would be the better choice, as it has a
narrower interaxial, and thus can shoot a little closer.  But in either
case, if you get closer than 7 feet to the subject, you will have to
restrict your background. Keep your subject matter between the f5.6 marks
on your depth of field scale. For example, if your near point is 5 feet
from the camera, you don't want anything closer than 20 feet. Try to get
some close-up masks for mounting; you will need to crop the edges a bit
more than a "normal" stereo.

Also, be aware when taking closeups with these cameras, you will get some
distortion--the image will stretch on the z-axis, as the lenses are too far
apart for close-ups. But the stereos will still be useful, and certainly
better than flatties! IMHO!
I've had better results in such situations with my Verascope F40, and
cropping down to 5 perfs. I know that isn't of immediate help to you, but
in time you might want to consider some other cameras for this application.

Another possibility would be to mount afocal converters on a camera, to
increase the effective focal length. This is probably not practical for
your upcoming surgery, as these aren't exactly off-the-shelf items. Charles
Piper's Technical Pages #94 & 95 discusses this.

>Hope this isn't a stupid question, and thanks in advance.

There are no stupid questions, just silly answers, like my botched
explanation of LCDs a couple days ago. Thankfully, there are a few people
on P3D who know what they're talking about, or at least check their facts
before mouthing off. ;-)

Tony Alderson
aifxtony@xxxxxxx



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