LensCalc

Shutter Speed Calculator

How slow can you hand-hold this lens?

Focal Length (mm)

Crop Factor

Stabilization (stops)

Slowest Handheld Shutter

1/50 s

Equivalent Focal Length: 50 mm
In Seconds: 0.02

What you entered

Focal Length (mm): 50Crop Factor: 1Stabilization (stops): 0

1
Full-frame equivalent focal length
50 mm x 1= 50 mm
2
Reciprocal rule baseline
1 / 50= 1/50 s
3
Allowance for 0 stop(s) of stabilization
1/50 x 2^0= 1/50 s

Result

Slowest Handheld Shutter: 1/50 s

Handheld shutter speed by the reciprocal rule

The reciprocal rule says use a shutter speed at least as fast as 1 over the full-frame equivalent focal length. Each stop of stabilisation doubles the time you can hold.

Lens	Crop factor	Stabilisation	Effective focal length	Minimum shutter
24 mm	1	None	24.0 mm	1/24 s
50 mm	1	None	50.0 mm	1/50 s
50 mm	1.5	None	75.0 mm	1/75 s
100 mm	1	None	100.0 mm	1/100 s
200 mm	1	None	200.0 mm	1/200 s
200 mm	1	3 stops	200.0 mm	1/25 s
400 mm	1.5	4 stops	600.0 mm	1/38 s

The rule dates from 35mm film and is optimistic on high-resolution sensors, where camera shake shows up more readily. Treat it as a floor and go faster when you can. It addresses camera shake only, not subject movement.

The reciprocal rule

As a baseline, use a shutter speed at least as fast as 1 over your effective focal length — 1/200s for a 200mm lens. Longer lenses magnify hand shake as much as they magnify the subject, so the safe speed scales directly with focal length.

Crop factor tightens the rule

A 50mm lens on an APS-C body frames like a 75mm, and it magnifies shake like one too. Multiply by the crop factor before taking the reciprocal, or you will consistently choose a shutter speed about a third too slow.

Frequently asked questions

I'm shooting with a 200mm lens on a 1.5x crop body — what's the minimum shutter speed?

Effective focal length is 200 × 1.5 = 300mm. The reciprocal rule says use at least 1/300s. In practice, round up to the nearest standard speed: 1/320s or faster.

How is the shutter speed calculator different from the time-lapse calculator?

The shutter speed calculator finds the minimum speed for sharp handheld photos. The time-lapse calculator plans shooting intervals and clip length for automated multi-frame sequences — different problems, different time scales.

Does image stabilization let me break the reciprocal rule?

Yes. Modern IBIS and lens stabilization claim 5-7 stops of correction. With 5 stops, a 200mm lens could theoretically hand-hold at 1/6s instead of 1/200s — though real-world results are usually 3-4 stops better, not the full claim.