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Master the art of modern photography
This month: Shutter speeds
Capturing well-exposed, sharp and accurately focused photographs can be fairly simple to do. With a typical digital camera set to fully automatic mode, all you have to do is point and shoot – it really is that simple. Of course, the one thing a camera can’t do is read the mind of its user and often, the result does not match the photographer’s intentions. Taking control of the camera and its settings is the only way.
In this Camera Clinic series, we will dig deep into the core features of modern cameras, offering advice on how you can make the most of their features to achieve photographs to be proud of. We kick off this series with one of photography’s fundamental tools, the camera shutter and its role in determining the exposure.
Exposure is about allowing the right amount of light to reach the camera’s sensor to give a correctly exposed photograph, which we can define as a picture with highlights that are not ‘blown out’ and shadows that are not blocked up, with a full range of tones in between.
The three exposure parameters, often referred to as the ‘trinity’, include the aperture, which is the size of the hole or iris in the lens that determines how much light passes through to the sensor, and the shutter speed, which is the actual length of time that the sensor is exposed to light. The third variable, ISO, is not a physical control but a measure of the sensor’s sensitivity to light with higher speeds achieved with signal amplification.
As we said, the camera can do the heavy lifting so all you have to do is snap away, but that’s no fun. What is more fulfilling is using the exposure triangle to give a result that matches your interpretation of the scene. So let’s take a look at the potential of the camera’s shutter speed range…
Getting the knowledge
The shutter times precisely how much light reaches the sensor or film. Most cameras have a range from 30 secs to 1/8000 sec, with the most used speeds in the region of 1/60 sec to 1/250 sec. In a daylight scenario, where the exposure is 1/125 sec at f/11 (let’s assume the ISO is fixed at 100) changing the speed to 1/60 sec doubles the amount of light reaching the sensor. To avoid overexposure, the aperture must be stopped down by one f/stop to f/16. Changing the shutter to 1/250 sec halves the light reaching the sensor, so to achieve the correct exposure, the aperture must be opened up by one stop to f/8. Maintaining this reciprocal relationship between the aperture and s
