HOW IT IS CALCULATED
Estimate a hand-holdable shutter speed
50 mm on full frame → about 1/50 s
Instant resultClear formulaRuns locally
01Values
021 ÷ (focal length × crop factor)
03Result
50 mm on full frame → about 1/50 s
The reciprocal rule is only a guideline
Stabilization, technique and subject motion can require faster or allow slower shutter speeds.
02
In short
What logic does the calculator use?
1 ÷ (focal length × crop factor)
Example?
50 mm on full frame → about 1/50 s