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Exposure
Help in Setting Aperture and Shutter Speed
A few seconds at the amusement park.
A 6-hour exposure in the Sierra.
Given the information and examples above you ought to have some idea of the aesthetic results you're trying to
achieve. If you're interested in the blurring or stopping of motion on film, set the shutter speed first. If you're
interested in what will be in focus, set the aperture first. If you can't get a combination that suits you, look for a
different speed of film or put a neutral density filter over the lens to reduce the amount of light coming through
without changing what is in focus.
How do you know that you're send the right number of photons through to the film so that your result won't be
completely black (underexposed slide) or completely white (overexposed slide)? Old-timers using negative film
would simply estimate the exposure from their experience, then fix up any minor errors in the darkroom. A
somewhat more accurate technique is to RTFM. Here are the instructions included with Kodak Tri-X, a name
shared by two confusingly different films (Tri-X Pan is ISO 400 and has good midtone separation; Tri-X Pan
Professional is ISO 320 and has more highlight separation):
"Use the exposures in the table below for frontlighted subjects from 2 hours after sunrise to 2 hours
before sunset."
http://www.photo.net/making-photographs/exposure (8 of 13)7/3/2005 2:22:14 AM