Glossary of over 1000 photography terms

Reciprocal rule

Rule of thumb which states that the minimum shutter speed for sharp hand-held shots is the reciprocal of the lens focal length. Eg for a 200mm lens the minimum safe shutter speed is 1/200sec.

For crop frame cameras the 35mm equivalent focal length should be used in the calculation.

Lenses and camera bodies with optical stabilisation can produce sharp results at slower shutter speeds.


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