Lesson 6: Shutter Speed: Freezing and Blurring Motion

Shutter speed is how long the shutter stays open, measured in seconds or fractions of a second. It is the exposure control that deals with time: a fast shutter speed freezes a moment, and a slow shutter speed lets movement smear across the frame. Like aperture, it is both a technical setting and a creative choice.

The full-stop shutter speed sequence is 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2 and 1 second. Each step doubles or halves the time the sensor is exposed, and therefore doubles or halves the light. Modern cameras offer intermediate third-stop steps (1/320, 1/160 and so on), and can go far beyond the ends of this sequence: many cameras reach 1/8000 of a second at the fast end, and can hold the shutter open for 30 seconds or, in bulb mode, for as long as you hold the button.

Freezing Motion

To freeze a fast-moving subject you need a fast shutter speed. A walking person is sharp at 1/250, a runner at 1/500, and a bird in flight or a footballer striking a ball may need 1/1000 or 1/2000. The faster the subject moves across the frame, and the closer it is, the faster the shutter speed you need. Photographers of sport and wildlife live at the fast end of the scale, and accept the cost: a fast shutter lets in little light, so they must open the aperture or raise the ISO to compensate.

But blur is not always the enemy. A slow shutter speed turns a waterfall into silk, car headlights into ribbons of light, and a panning shot — where you follow a moving subject with the camera — keeps the subject sharp against a streaked background, giving a powerful sense of speed. The choice between freezing and blurring is a choice about what the photograph should say: frozen motion shows a moment with forensic clarity; blurred motion shows energy and time passing.

Camera Shake and the Reciprocal Rule

Slow shutter speeds have a second cost: your own hands shake. Below a certain speed, the whole image blurs, not just the moving parts. A useful guide is the reciprocal rule: to hand-hold safely, use a shutter speed at least as fast as one over the focal length — 1/50 for a 50 mm lens, 1/200 for a 200 mm lens. Image stabilisation in the lens or body can buy you two or three extra stops, and a tripod removes the limit entirely, which is why landscape and night photographers always carry one.

When you shoot, ask two questions: how fast is my subject moving, and how steady can I hold the camera? Set the shutter speed for the answer, then adjust aperture and ISO around it. That is shutter priority mode in a nutshell — and a good way to learn the triangle one corner at a time.