What is the reciprocal rule for shutter speed?

The reciprocal rule states that your minimum handheld shutter speed should be 1 divided by your effective focal length. For example, with a 50mm lens on full frame, use at least 1/50s. On APS-C (1.5x crop), that becomes 1/75s. This prevents camera shake blur in handheld shots.

How does image stabilisation affect shutter speed?

Image stabilisation (IS, VR, OIS, IBIS) lets you shoot at slower shutter speeds without camera shake. Each stop of stabilisation doubles the usable exposure time. A 3-stop IS system on a 200mm lens lets you shoot at 1/25s instead of 1/200s for static subjects.

What shutter speed freezes action?

Walking people: 1/125s. Running or cycling: 1/500s. Sports and birds in flight: 1/1000s to 1/2000s. Motorsport: 1/2000s or faster. These are guidelines — the actual speed needed depends on the subject distance and direction of movement relative to the camera.

Does sensor crop factor affect required shutter speed?

Yes. A crop sensor magnifies both the image and any camera shake. A 50mm lens on a 1.5x APS-C sensor has the same field of view as 75mm on full frame, so you need at least 1/75s handheld instead of 1/50s. Always use your effective focal length in the reciprocal rule.

PhotoCalcs

Shutter Speed Calculator — Recommended Shutter Speed

Find the right shutter speed for your subject, focal length and stabilisation to avoid camera shake and motion blur.

Focal Length

Your lens focal length

Crop Factor

Full frame = 1, APS-C = 1.5

Subject MotionHow fast is your subject moving?

StabilisationImage stabilisation system

How We Calculate This

This calculator uses the reciprocal rule and motion guidelines to recommend shutter speeds:

Reciprocal Rule

Minimum shutter speed = 1 / (focal length x crop factor)

Stabilisation Benefit

Stabilised minimum = reciprocal speed x 2^(IS stops)

For moving subjects, the calculator recommends speeds based on typical subject velocities, independent of focal length — since motion blur is determined by the subject speed relative to the sensor, not just camera shake.

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Last updated: February 2026

All calculations are estimates based on standard optical and photographic formulas. Results may vary with specific equipment.