The reciprocal rule says the slowest handheld shutter is about 1 ÷ (focal length × crop factor). Image stabilization buys extra stops; high-resolution sensors need a safety margin.
Enter your lens and camera to get a realistic number.
How it works
t = 2^IS ÷ (f × crop × k).
FAQ
Does stabilization freeze moving subjects?
No — it only reduces camera shake. Moving wildlife still needs fast shutter speeds.
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