Shutter speed: freeze or blur
Shutter speed is how long the sensor collects light. Learn how it halves and doubles in stops, how fast is fast enough to freeze a child running or your own shaky hands, and when blur is the point.
Shutter speed
How long the sensor collects light for one photo, written in fractions of a second: 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, and on to 1 second and longer. Each step doubles or halves the time, so each step is one stop. Longer time means more light, and also more chance of blur. Phones use an electronic shutter instead of a moving curtain, but the idea is identical.
1/125 is twice as long as 1/250, so it lets in twice the light: one stop brighter.
Check yourself
Sara changes her shutter speed from 1/250 to 1/125. What does that do?
- Halves the time, so one stop less light
- Makes the shutter faster, so there's less blur
- Doubles the time, so one stop more light and more risk of blur
- Nothing noticeable; the two are almost the same
Show the answer
Doubles the time, so one stop more light and more risk of blur
Right. 1/125 of a second is twice as long as 1/250: one stop more light, and twice as long for anything to move.
Two different blurs
Motion blur: the subject moved
A car is a streak, a child's arms are smudged, but the wall and the ground behind them are sharp.
Fix: a faster shutter speed.
Camera shake: you moved
Everything is smeared or doubled in the same direction, including things that were perfectly still, like buildings and signs.
Fix: a faster shutter, steadier hands, stabilisation or a support.
Check yourself
In Nima's photo, his friend's bike is a streak, but the brick wall right behind it is crisp. Shake or motion blur?
- Motion blur: the bike moved while the shutter was open, so a faster shutter would freeze it
- Camera shake: his hands moved, so he should hold the phone steadier
- Neither: the phone focused on the wall instead of the bike
- Both equally, since any blur is the same thing
Show the answer
Motion blur: the bike moved while the shutter was open, so a faster shutter would freeze it
Right. The still wall came out sharp, so the camera itself was steady. Only the bike moved during the exposure: motion blur, fixed with a faster shutter.
Step through it
1/1000: the ball is frozen A ball keeps crossing the frame at a steady speed, in front of a post that never moves. At 1/1000 of a second the shutter is open so briefly that the ball hardly travels, so the picture catches it as a crisp, round ball.
1/60: a short streak At 1/60 the shutter stays open long enough for the ball to travel a little while light is being collected, so it records as a short streak. The post didn't move, so it stays sharp: this is motion blur.
1/8: three stops more light, a long blur At 1/8 the shutter is open about eight times as long as at 1/60: 1/60 to 1/30 to 1/15 to 1/8 is three stops, marked +3 stops. The whole frame is brighter and the ball smears into a long, faint streak. That's lovely for flowing water and bad for faces.
1/15 in a shaky hand: everything doubled At 1/15, held in an unsteady hand, the whole frame comes out doubled in the same direction: the post, the ground line and the ball's streak. When still things are doubled too, the camera moved. That's camera shake, not subject motion.
Check yourself
In the 1/15 frame, the post looks doubled because the post itself moved while the shutter was open.
Show the answer
False
False. The post never moves. It's doubled because the hand holding the camera moved, which shifts everything in the picture the same way. That's the tell-tale sign of camera shake.
FAST ENOUGH
A rough freezing guide
How fast you need depends on how quickly the subject moves, how close it is and which way it crosses the frame, so treat these as starting points: people walking about 1/250; children running, pets, sports about 1/500 to 1/1000; a bird's wings 1/2000 or faster. Something moving straight towards you needs less speed than the same thing crossing the frame.
Mina's niece runs across the park. At 1/125 her legs are a blur; at 1/1000 every lock of hair is frozen in the air.
YOUR OWN HANDS
The handheld rule of thumb
To avoid shake when holding the camera, use a shutter speed of at least 1 / (focal length in mm), using the full-frame equivalent focal length. A 50 mm lens: 1/50 or faster. A 200 mm zoom: 1/200 or faster. A phone's main lens, roughly 24 to 28 mm equivalent, is forgiving. Image stabilisation, in the lens, the camera body or the phone, buys you roughly a few extra stops for still subjects. But it only steadies your hands; it can't freeze a subject that's moving.
With stabilisation, Reza can often get a sharp photo of a still building at 1/15 on his phone. A person walking past in that same photo will still be blurred.
Check yourself
Sara is holding her camera with an 85 mm lens and no stabilisation. By the rule of thumb, what's the slowest shutter speed she should use?
- 1/15, because shorter lenses need less speed
- 1/30, the standard for any lens
- 1/1000, the only safe speed for a long lens
- About 1/85, so in practice 1/100 or 1/125
Show the answer
About 1/85, so in practice 1/100 or 1/125
Right. 1 divided by 85 is about 1/85. Cameras don't have that exact setting, so round to the next faster one, 1/100 or 1/125.
BLUR ON PURPOSE
When slow is the point
A slow shutter isn't only a risk. Water turns silky at about 1/2 second to several seconds, with the camera on a tripod or braced on a rock. Car lights draw trails at night over several seconds. Panning, following a cyclist with the camera at about 1/30 to 1/60, keeps the rider fairly sharp and streaks the background into speed lines. Camera: S or Tv mode, shutter priority, lets you pick the time while the camera sets the aperture. Phone: Pro mode often has an S setting, and features like Night mode or long-exposure effects lengthen the capture for you.
Nima rests his phone on a bridge railing, sets S to 1 second in Pro mode, and the stream below turns into white mist.
Check yourself
Match each shot to a sensible shutter speed
Show the answer
- A friend walking towards you → About 1/250
- A child running across a park → About 1/500 to 1/1000
- A bird's wings in flight → 1/2000 or faster
- Silky waterfall water, on a tripod → About 1/2 second or longer
Habits against shake
- Two hands, elbows in
Hold the phone or camera with both hands and tuck your elbows against your body. A phone held out at arm's length in one hand wobbles most.
- Lean on something
A wall, a doorframe, a table or a railing turns your body into a steadier support.
- Breathe out, press gently
Take the shot at the end of a slow breath out, and squeeze the button rather than stabbing it.
- Take the hand out of it
Use the 3-second timer, the volume button or a remote so pressing doesn't jolt the camera.
- Check before you blame the lens
If a picture looks soft, zoom in. If everything, background included, is doubled the same way, it was shake, not focus.
Check yourself
Mina wants the waterfall on her hike to look like soft white silk. What setup should she use?
- 1/1000 held in her hand, to capture every drop
- A slow shutter, about 1/2 second or longer, with the camera steadied on a tripod or a rock
- 1/60 held in her hand, the usual everyday setting
- Any speed, then add blur in an editing app
Show the answer
A slow shutter, about 1/2 second or longer, with the camera steadied on a tripod or a rock
Right. The water needs time to smear into silk, about 1/2 second or more, and the camera must stay still for all that time so the rocks around it stay sharp.
Lesson recap
- Shutter speed is how long the sensor collects light; each step (1/250, 1/125, 1/60 ...) is one stop.
- Longer times bring more light and more risk of blur.
- Motion blur means the subject moved; camera shake means you moved, and then everything is doubled.
- Roughly: walking about 1/250, running children about 1/500 to 1/1000, birds' wings 1/2000 or faster.
- Handheld, use at least 1 over the focal length; stabilisation steadies hands but can't freeze a moving subject.
- Slow on purpose, with support, gives silky water, light trails and panning shots.