Reciprocal Shutter Speed Calculator
Estimate the slowest handheld shutter speed for a focal length and crop factor (1 / effective FL).
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The reciprocal rule
A classic handheld guideline: use a shutter speed of at least 1 / effective focal length (seconds). Effective focal length = focal length × crop factor. Stabilization and good technique allow slower speeds.
FAQ
Does IBIS change the rule?
Yes. In-body and lens stabilization often buy 3–7 stops. Still start from the reciprocal value, then test how far you can push it.
Stabilization and modern practice
In-body and optical stabilization can add several stops, but performance varies with focal length, shutter type and technique. Use the reciprocal result as a baseline, then test one or two stops slower. For video, reciprocal thinking still helps when choosing shutter angles near 180 degrees: effective exposure time should remain short enough for handheld stability if no gimbal is used.