> Mainly uncollimated (non-laser) light spreads out the further away from a
> hole. The amount of light varies directly according to the hole size and
> indirectly according to the distance from the hole to the film.
Okay, I think I get it -- this happens because the diaphragm moves away
from the film when you mount a lens on tubes, so when the diaphragm's
further away, the light that does get through it has more room to spread out
by the time it reaches the film, so the resulting image is darker. (ie,
subject distance doesn't actually matter here)
Presumably that implies that if you had a camera where the diaphragm was in
the body this wouldn't happen -- but, thinking about it, I'm not sure how
you'd design that without a whole lot of other weird optics cropping up.
-- dan
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|