Handheld Shutter Speed Calculator
The slowest shutter speed you can shoot handheld without visible shake.
Results
- Slowest safe handheld shutter speed
- 1/50
- Nearest setting on your camera
- 1/50
Stay at or faster than this shutter speed to avoid visible camera shake blur when shooting handheld.
The closest speed on the standard third-stop dial. If it rounds slower than the figure above, pick the next speed up to stay on the safe side.
How it works
The reciprocal rule says the slowest safe handheld shutter speed is one over the effective focal length: 1/50 second for a 50mm lens on full frame, 1/200 for a 200mm. Longer lenses magnify your own movement as much as they magnify the subject, so the tolerance shrinks in proportion.
On a crop sensor the effective focal length is what matters, since the sensor enlarges any shake along with the image. A 50mm on APS-C needs roughly 1/75 rather than 1/50.
Image stabilisation buys back time in stops, and each stop doubles the speed you can get away with. Manufacturer claims are measured under generous laboratory conditions, so knocking a stop off the advertised figure is a reasonable working assumption. Note too that stabilisation corrects camera shake, never subject motion: a moving person needs a fast shutter no matter how good the IS is.
The formula
t = (1 / (f × crop)) × 2^IS stops
f is the focal length in mm and crop the sensor's crop factor. More stabilisation stops allow a longer exposure.
Frequently asked questions
- Is the reciprocal rule reliable?
- It is a starting point calibrated for film-era print sizes. Examined at 100% on a high-resolution sensor, many photographers need one to two stops faster than the rule suggests to get genuinely critical sharpness.
- Does stabilisation help with moving subjects?
- No. It compensates for your movement, not theirs. Freezing a walking person needs around 1/125 or faster regardless of what your IS is doing.
- Should I trust the advertised IS stops?
- Treat them as a best case. Ratings come from standardised bench tests, and real-world results depend on your stance, breathing, and whether you are braced against anything. Assuming one stop less than claimed is prudent.
Read more about this
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- ND filters and the arithmetic of long exposureThree different labelling systems for the same piece of glass, and a conversion that is one line of arithmetic once you stop trying to memorise a table.