semicircles in sky -Reply

["Timothy E. Coffer" <COFFER.TIM@xxxxxxxxxxx>]

Joseph, are you using a wide-angle lens? I get these "rainbows" with
the 17-28mm Vivitar and sometimes on the 35mm side of the 35-200mm
Nikkor. I dare say they aren't present in the prints of such affected
frames, although that surprised me (on a positive note).
Perhaps someone else in the group could elaborate on the cause. Must
be something optically.

>>> "Joseph Demanuele" <jdemanuele@xxxxxxxxxxxx> 10/01/97 04:36am
>>>
Hi everyone!

I use the Kodak B&W emulsion rated at 400ASA (it is very sunny in Malta
- -lots of IR !). I normally use a standard red filter and develop in Rodinal
1+25 for 10 minutes at 24 degrees. My problem is that I sometimes get
large
semicircular arcs over the sky. These span all the sky in the image and
look like multiple rainbows (in B&W of course).
Has anyone got any idea about what's causing this!

BTW I normally use a minolta 600si and meter through the lens with the
filter attached. This seems to give an adequate exposure  a lot of the
time.

Joe 



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