Motion blur appears when something moves across the frame while the shutter is open. The longer the shutter is open, the further the subject travels during the exposure and the longer the streak it leaves. Shutter speed is therefore the control that decides whether movement is frozen or shown.
Two sources of blur
- Subject motion: the subject moves, the camera is steady. Only the moving parts are blurred; the rest of the scene is sharp.
- Camera motion: the camera moves during the exposure. Everything in the frame is blurred in the same direction.
Telling them apart matters, because the cures are different. A tripod or stabilisation fixes camera motion. Only a faster shutter speed fixes subject motion.
What determines how much blur you get
Blur depends on how far the subject’s image moves across the sensor during the exposure. Four things affect that.
- Speed of the subject. A racing car needs a much faster shutter than a person walking.
- Direction of movement. A subject crossing the frame blurs far more than one coming straight towards the camera at the same speed.
- Distance. A nearby cyclist sweeps across the frame quickly; one in the distance barely moves.
- Focal length. A telephoto lens magnifies movement along with everything else.
Parts of a subject also move at different speeds. A runner’s body may be sharp at 1/250 s while the hands and feet are blurred. A bird’s body freezes at 1/1000 s while the wingtips need 1/3200 s.
Shutter speeds to freeze motion
| Subject | Minimum shutter speed |
|---|---|
| Person standing, posing | 1/125 s |
| People walking | 1/250 s |
| Children playing, pets | 1/500 s |
| Running, cycling, team sport | 1/1000 s |
| Birds in flight, motor sport | 1/2000 s or faster |
| Water splashes and droplets | 1/2000 s or faster |
These are for subjects fairly close and moving across the frame. Subjects that are distant or moving towards the camera tolerate slower speeds.
Using blur on purpose
A perfectly frozen moving subject can look static, as if parked. Controlled blur communicates speed and the passing of time.
Subject blur with a steady camera
Put the camera on a tripod and let the moving element blur against a sharp setting. Flowing water turns silky at 1/2 s to 2 s. A crowd in a station becomes ghostly at 1 s. Car headlights form continuous trails at 10 s to 30 s.
Panning
Panning reverses the idea: the camera follows the subject, so the subject stays reasonably sharp and the background streaks. Stand side-on to the subject’s path, start tracking before pressing the shutter, press gently and keep swinging smoothly after the shot. Start with 1/60 s for a cyclist or 1/125 s for a car, then try slower speeds as your technique improves. Expect many failures; a success rate of one in ten is normal at first.
Getting slow speeds in daylight
In bright conditions even ISO 100 and f/16 may give 1/125 s, which is too fast for visible blur. A neutral density (ND) filter is dark glass that reduces the light entering the lens. A 6-stop ND filter turns 1/60 s into 1 s; a 10-stop filter turns it into about 15 s. Working at dawn, dusk or in deep shade achieves a similar result without a filter.
Common mistakes
- Using Auto mode for action. The camera does not know the subject is moving and may choose 1/60 s.
- Choosing a speed that is neither one thing nor the other, such as 1/60 s for a runner. The subject is slightly blurred, which looks like an error. Commit to freezing or to obvious blur.
- Attempting long exposures handheld.
- Stopping the pan at the moment of pressing the shutter.
- Forgetting that a faster shutter needs more light. Open the aperture or raise ISO to compensate.
Practice exercise
- Stand beside a road with steady traffic or a cycle path. Use Shutter Priority with Auto ISO.
- With the camera held still, photograph passing vehicles at 1/1000, 1/250, 1/60 and 1/15 s. Compare how blur grows.
- Set 1/60 s and pan with ten passing vehicles. Review which frames have a sharp subject and a streaked background.
- Repeat the panning at 1/30 s and compare your success rate.
Next in this series: Fast vs Slow Shutter Speed Examples, What Is Shutter Speed? and How to Balance ISO, Aperture and Shutter Speed. You can also browse all photography lessons.
