k
2011-01-26 01:29:41 UTC
Back when I lectured, I would often find students grumbling about the lenses
in the photo store (we lent out camera kits), blaming them for their fuzzy
images or the white spots on their prints. More oft than not it was their
poor efforts at focusing their enlargers or rough handling of negs - but
they'd decline to see that logic.
If I had the time, I'd whip off a print to show them their neg was in fact
fine, their lens fine, and they'd be better off spending time paying
attention to their lecturer in the darkroom classes, try to focus the
enlarger and maybe occasionally store their negs somewhere other than the
bottom of their bag .. If I had less time I'd wave a cat lens at them and
ask them if they thought the big black circle in the front of the lens would
degrade the image quality <blank stares>.
Sometimes I'd demonstrate (less dramatically than the link below) that since
nothing in the optical pathway was in focus, the gunk they saw on their
film, scans, prints or whatever was more a consequence of mistreatment of
the negatives than anything relating to the lens - and I showed this by
sticking a piece of electrical tape across a lens - white demonstrated a
general lowering of contrast - black showed basically a reduction in light
levels .. and I tried to tell them THAT was why you fixed deep scratches in
a lens by painting them black ! =)
A decent box lens hood could almost eliminate the net effect of a piece of
white tape.. and overall, a lens hood went a lot further to preserving
maximum contrast and sharpness than giving the lens a good clean ever did ;)
like I said though, this is dramatic
http://kurtmunger.com/dirty_lens_articleid35.html
in the photo store (we lent out camera kits), blaming them for their fuzzy
images or the white spots on their prints. More oft than not it was their
poor efforts at focusing their enlargers or rough handling of negs - but
they'd decline to see that logic.
If I had the time, I'd whip off a print to show them their neg was in fact
fine, their lens fine, and they'd be better off spending time paying
attention to their lecturer in the darkroom classes, try to focus the
enlarger and maybe occasionally store their negs somewhere other than the
bottom of their bag .. If I had less time I'd wave a cat lens at them and
ask them if they thought the big black circle in the front of the lens would
degrade the image quality <blank stares>.
Sometimes I'd demonstrate (less dramatically than the link below) that since
nothing in the optical pathway was in focus, the gunk they saw on their
film, scans, prints or whatever was more a consequence of mistreatment of
the negatives than anything relating to the lens - and I showed this by
sticking a piece of electrical tape across a lens - white demonstrated a
general lowering of contrast - black showed basically a reduction in light
levels .. and I tried to tell them THAT was why you fixed deep scratches in
a lens by painting them black ! =)
A decent box lens hood could almost eliminate the net effect of a piece of
white tape.. and overall, a lens hood went a lot further to preserving
maximum contrast and sharpness than giving the lens a good clean ever did ;)
like I said though, this is dramatic
http://kurtmunger.com/dirty_lens_articleid35.html