Shutter speed is the length of time the camera shutter is open, exposing light onto the film. In short, it’s how long your camera spends taking a photo. The longer the shutter speed, the more you expose, the shorter the shutter speed, the less you expose.
In order to understand how and why you select a specific shutter speed, you must first understand the function of the shutter itself. Whilst the amount of light entering the lens is down to the aperture selection, the shutter is what separates the light from the film until the shutter is compressed. When the shutter is pressed, the shutter will open and then close for the measured time that you have selected, making an exposure. This shutter is often referred to as a curtain, which can be made from cloth or of a mechanical, bladed shutter.
You will have the fastest shutter speed relative to the ability of your camera which will largely be a number anywhere from 500 to 8000. This number, using the common top speed of mid specification cameras of ‘1000’ as an example relates to a fraction of a second, so ‘1000’ actually means 1/1000th of a second, so blistering quick and only allowing in a tiny amount of light comparatively. Below this you will ordinarily find settings in increments of this, so 500, 250, 125 etc. This continues on to speeds of quarters of a second ‘4’, a half second at ‘2’, ‘1’ as a whole second and then at the beginning of your selection you will find ‘B’ which stands for Bulb. This means that the shutter will stay open for as long as your finger is compressed on the shutter button giving you manual control, ideal for long exposures.
How you use the shutter speed will depend on the necessity of your exposure and your creative intent. The higher the number selected, which to reiterate equals the fastest, the less affect the shutter will have creatively, it is effectively freezing time, something we all associate with taking photos. As this number gets lower however, below 250 you will start to see some blurring when there is movement in the frame, more noticeable below 60 or 30. This can be used to great visual affect creatively if that is your intention. For example a runner shot at 1000 will be rendered stationary in mid air but at 60 you will see movement in the background and blurring, giving the visualisation of the speed.
If a lower selection of shutter speed is made on necessity, for example you are shooting later in the day and need as much light to enter as you can, it is worth noting that between 60 and 30 the action of the shutter through the camera causing a small shake which can affect your exposure and final image. You can sometimes combat this with a relaxed grip when taking the shot, but certainly anything below 30 will require a tripod of some kind. A long exposure notably affects any light in the frame most noticeably, especially that of something that is moving such as a car. From the beginning of the shutter opening until it closes, anything in the frame will leave a trace of where that light has been.
The connection between aperture and shutter is one of balance. If you are wanting a shallow depth of field, allowing in a lot of light through the lens itself, you are prioritising how your image will look and the shutter speed will need to counteract this, so depending on the weather and meter reading, you will use a higher shutter speed. On the opposite side of the scale, if you wanted to show blur and movement within the image and selected 60 for example, you may want an aperture of f.8 to f.16 or above depending on the brightness of the day.
Cameras from the late seventies and eighties onward may also have a shutter priority function. This simply allows you to choose your preferred shutter speed and it will automatically choose an aperture selection to balance this and give you a good exposure.
Whilst light meters will often tell you how to set your shutter speed or aperture, or even do this for you automatically, it is good to know the fundamentals so that, in a pinch you can make adjustments on the fly and have greater creative control over your selections when shooting manually.
Words by Chris Taylor