Shutter Speed

Shutter speed is described as the unit of measurement which determines how long the camera shutter remains open as each picture is taken. The slower the shutter speed, the longer the exposure time. The shutter speed and aperture together control the total amount of light reaching the sensor.

There are two particular aspects that shutter speed is responsible for: changing the brightness of the photo, and creating dramatic effects by either blurring motion or freezing action. Shutter speed exists because of camera shutters – each of which is a curtain in front of the camera sensor that stays closed until the camera fires. When the camera fires, the shutter opens and fully exposes the camera sensor to the light that has passed through the lens. After the sensor has finished collecting the light, the shutter closes immediately, stopping the light from hitting the sensor.

When one uses a long shutter speed, they end up exposing their sensor for a significant period of time. The first big effect of it is motion blur. If the shutter speed is long, moving subjects in the photo will appear blurred along the direction of motion. This effect is used quite often in advertisements of cars and motorbikes, where a sense of speed and motion is communicated to the viewer by intentionally blurring the moving objects. On the other hand, slow shutter speeds are generally used to photograph objects at night, or in dim environments with a tripod.

Shutter speed can also be used to obtain opposite results through the concept of freeze motion. With efficient use of a particularly fast shutter speed, one can eliminate motion even from fast-moving objects, such as birds in flight, or cars driving past.

The other important effect of shutter speed is exposure, which relates to the brightness of an image. If a long shutter speed is used, the camera sensor gathers a large amount of light, meaning that the resulting photo will be rather bright. By using a quick shutter speed, the camera sensor is only exposed to a small fraction of light, resulting in a darker photo.

A fast shutter speed is typically whatever it takes to freeze action. If one is photographing birds, that may be 1/1000th second or faster. However, for general photography of slower-moving subjects, one might be able to take pictures at 1/200th second, 1/100th second, or even longer without introducing motion blur. Long shutter speeds are typically above 1 second – at which point, one will need to use a tripod to obtain sharp images. One would use long shutter speeds for certain types of low-light/night photography, or to capture movement intentionally. If anything in the scene is moving when using long shutter speeds, it will appear very blurry.

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