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Ken, what went wrong?! Half of my picture is too dark and half is too light. How did I mess up both ways in the same picture?
PROBLEM # 1: The half-dark/half-light picture.
SOLUTION: flash-sync speed
I
see this problem a lot. The camera's shutter speed was too high to use
with a flash.
In some cameras the shutter is like a tiny curtain that opens to expose
the film to light. In this case, before the curtain got completely open
the flash "flashed". So the part of the film that was open:
is correctly exposed by the flash. But the part that wasn't : is underexposed
and thus too dark.
You have to use a shutter speed that is slow enough for the curtain to have time to completely uncover the film before the flash goes off. The highest (fastest or shortest) shutter speed your particular camera can use and NOT get this problem is called the "flash-sync" speed. This flash-sync speed will be marked on the shutter-speed dial of your camera and mentioned in your camera's manual.
When a machine printer tries
to prints this botched negative, it will try to compensate for the too
dark side by lightening up the picture, so one side ends up being too
dark and one side too light. This can be helped in imaging editing programs
like Photoshop, but the results will still typically be unsatisfying.
A re-shoot is the only cure. Dig out that manual. Find out what your camera's flash syn speed is be prepared next time.
Ken Casey;
