"Peifer, William [OCDUS]" wrote:
> Here's my calculation, FWIW....
> To the extent that simple optics
> formulas apply (I think they do),
> your setup with the A100/2.8 will
> require an effective distance from
> lens to object of 150 mm, and an
> effective distance from lens to film
> plane of 300 mm.
I've not measured the distances, but with 68mm of extension
tube on the 100mm macro, I can pretty much get the image size
I want.
> If you're using a macro lens, then
> it's probably already pretty well-corrected
> for spherical aberration, so the
> corners/edges shouldn't be too far out of
> focus
I don't care about the corner sharpness, or even light fall
off. That part of the frame will be out of focus IAC, and
light fall off or lack of sharpness will only add to the
effect I'm trying for. I can see these things being aa
problem for other shots, though.
> (assuming your object is flat enough
> to be within the depth of field).
It is. At least this one particular shot is.
> I'd be interested to hear if your
> experimentally determined measurements
> come anywhere near these simple calculations.
See above - I think they're pretty close. When I actually set
the camera on the stand, and place the object on the platform,
I'll be able to take some measurements. Right now I've just
been hand holding the camera while swapping lenses to get a
sense of what might work.
> I can't wait to see your
> February PUG submission!
After all this it'll probably be pretty mediocre, and of
little interest to others except as a curiosity. It's
nothing special except that it's my first try at this sort of
photography. It's probably more interesting to me than anyone
else, and mostly from a technical perspective at that.
Thanks for all your suggestions. I better go to work <g>.
--
Shel Belinkoff
mailto:[EMAIL PROTECTED]
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