Why does my camera make a whirring noise during a long exposure?

Question

I have a Sony Alpha a55.

When I take a long exposure photo, while the shutter is open, the camera makes a whirring sound. What causes this noise and why is it necessary to the camera's operation? (I have interface sounds turned off — so I suppose this is some piece of the hardware physically making a noise.)

Asked by jtbandes

Answer

I'm familiar with Canon lenses featuring Image Stabilization that can emit a faint "whir" as IS operates. Your Sony body has a form of image stabilization built into the body, and if that's on during a long exposure, you might be hearing that as it operates.

If you're shooting long-exposure shots with the camera mounted on a tripod (which would be best), it's usually recommended that image stabilization be turned off (I believe this to be the case for your a55).

Answered by D. Lambert

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