Wednesday, July 14, 2010

Some Tips for Exposing Film with Artificial Light.


My students are in the middle of an artificial light project as I write. I wanted a chance to jot down a couple of suggestions, there are some common problems that can be avoided with some foresight.
  • Get a tripod. You will likely be exposing film at very long shutter times and your camera will move if you try to hand hold it. You can pick up an o.k. tripod at Target, Wal-Mart, Best Buy or Ritz photo here in Rochester. Also, the Technology Services office in the atrium will check out tripods to RCTC students with a current I.D. There is no reason to do this project without a tripod.
  • Use a cable release or your camera’s self-timer to trip the shutter. If you press the shutter with your finger while you are making a long exposure, you will make the whole camera shift. Even if you are using a tripod. A cable release is something you might still find at Ritz or Best Buy in Rochester, certainly, you could make a drive up to the cities and find one. Most of your cameras have self-timers, and that may be a better option.
  • You will need to adjust your exposure time for something called “Reciprocity Failure”. Film reciprocity is the property of film that lets us change f-stop and shutter speed combinations and still have a good exposure. For example, f.8 @ 125 is the same exposure as f.11 @ 60. When you are making really long or really short exposures, that all breaks down. Above is a chart Kodak produces for Tri-X film which indicates how to adjust your time if your exposure is longer than a half a second. It should work well for the Arista Premium we are using in class. According to the chart, if your indicated exposure is ten seconds, you should either open up two stops in the aperture, or expose for fifty seconds to get the proper exposure.
  • Meter for the light that is important. If you are photographing someone under a streetlight, be sure and walk right up to them and fill your viewfinder with their face. That will insure that the dark alley behind you isn’t throwing off your meter.
  • Bracket, Bracket, Bracket. If your camera indicates an exposure of one full second, you should also make exposures for ten seconds and a minute. You probably can’t overexpose, so go crazy.
  • Shoot one roll first, and take good notes. If you expose one roll under the lighting conditions you want to use, you can develop it by itself and figure out if you are on the right track before you invest too much time on the rest of the project. If you write down the frame number, f-stop and shutter speed, you will know which exposure times work and which don’t.
  • Have some fun, dang it. See what weird light sources work - try your car headlights, or a car spot-light. Try glow sticks. Try a campfire. Try a flashlight.

No comments: