Monday, October 5, 2009

Grain or Noise

In the bad old days of film, pushing film meant exposing the film at a higher ISO setting than that for which it was manufactured. The resulting image had greatly increased grain. The more you pushed, the greater the grain. Push 400 ISO film to 3200 ISO and the grain could get downright nasty.

Today's digital cameras also have an ISO setting at which they are most comfortable. This is the lowest ISO setting that the camera usually handles. 50 ISO or 100 ISO are common. Set the ISO higher and you are, in effect, pushing the CCD or CMOS chip with a resulting increase in electronic noise. This looks a lot like snow on a television screen.

To give you an idea of what happens when you set your ISO too high, I shot today's picture at 1600 ISO. I like the composition but hate the noise. In situations like this, if you must push the chip do it, but only if you must. If you can wait and take the picture under brighter conditions. Wait. You will be rewarded with much cleaner, stronger, more appealing pictures.

Personally, I prefer the image noise to the harsh and almost shadowless light from the on-camera electronic flash. Generally, the only time I prefer the on-camera flash is at parties when shooting couples and groups of posing friends. At these times, we are not going for art but clean record pictures.

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