The “holy trinity” of digital photography is aperture, ISO, and shutter speed, and learning what each of them are and how they work together is essential to consistently taking high-quality photographs.
Shutter speed 1/13, ISO 800, ƒ/5.6
What is shutter speed?
Shutter speed refers to the amount of time that the shutter is open. The shutter is a mechanism that opens and closes to allow light in through the lens to reach the image sensor. The longer the shutter is open, the more light can get through, and a faster shutter speed allows less light into the lens.
Take the above set of images, for example. The three quarters were spun, and photos were taken of the quarter at the same stage of motion. Yet, the image on the far left shows a drastic motion blur, while the image on the right seems not to be moving at all. This is because the shutter speed of the left hand quarter is much lower, at 1/25, whereas the one on the right is at 1/125. The image in the middle shows a quarter with a slight motion blur; it has a shutter speed of 1/80.
You’re probably wondering what 1/125 or 1/80 means. Shutter speed is measured in terms of seconds. A shutter speed of 1/125 means that the shutter was opened for 1/125th of a second. Depending on your camera, average shutter speeds range from 30 seconds (30″) to a lightning fast 1/8000th of a second. Many cameras can be much faster or slower.
The current world record for fastest shutter speed is 1/500,000,000. Built by a team of physicists, it’s called the STEAM camera (serial time-encoded amplified microscopy) and can take up to 6,000,000 photos continuously in a single second. Obviously it’s not a tool for everyday photography. You’ll rarely find even a shutter speed of 1/8000 useful. The range between 1/80 and 1/640 is often sufficient for most of your images.
Why shutter speed is important
Shutter Speed 1/10, ISO 1600, ƒ/3.5
Shutter speed allows you to control time and movement in photography. A fast shutter speed allows you to freeze time, stopping motion still. It also allows you to capture motion blurs that, when used creatively, can bring subject matter to life.
To freeze movement in an image use a faster shutter speed. Want to stop the motion of a bird’s wings mid-flight? Go to 1/640 or higher. To capture motion blur, slow it down. The above image was taken in a relatively dark room with a slower shutter speed. You can easily see the reactions of the people around the dancer, because even though the shutter speed is slow, they were standing still while the dancer in the middle is caught mid-motion. The longer exposure also allowed more light to reach the image sensor, so that the room looks well-lit, even though it wasn’t.
The relationship to aperture and ISO
While shutter speed establishes how long the shutter is open, thereby allowing light into the lens, it works directly with aperture to determine just how much light will be let in. A narrow aperture will let in less light, and this will set a range for your shutter speed. The aperture determines the volume of light that can enter the lens, whereby the shutter speed allows for the amount of time it can enter. Thus, long exposures and wide apertures lead to very bright photos, and short exposures and narrow apertures lead to darker photos.
As you would expect, shutter speed is also closely related to ISO. The two images above show the same scene, and both have an ISO of 800. Yet, the image on the right has a better exposure and more color detail than the one on the left. This is because the image on the left has a shutter speed of 1/4000, while the one on the right is 1/2000.
None of these three elements work well isolated from one another. Whenever you adjust one, be mindful of how it will affect the other two. A slower shutter speed will mean a brighter image, but if your ISO is too high or your aperture too wide, your image will be overexposed. Remember to adjust accordingly.
What you can do with it
Shutter Speed 10″, ISO 800, ƒ/10
You can create ghosts. Use a tripod or stable surface and slow shutter speed. The above image was taken with an exposure of 10″ (10 seconds). Put your subject in the frame, and then have them leave the frame halfway through the exposure, and they will become see through.
With shutter speed, your options are unlimited, as it allows you to effectively manipulate time and motion. It gives you the opportunity to be creative with movement, or to freeze a moment with perfect clarity.