Camera shutter cheat sheet: a jargon-free guide to understanding how it all works

Camera shutter cheat sheet: understanding shutter speeds, curtains and how it all works

The shutter speed is one of two fundamental controls for regulating the brightness of your pictures. Your camera’s shutter speed setting works in tandem with the aperture to ensure that you can get a perfect exposure in a huge variety of lighting conditions.

Shutter speeds are easier to understand than apertures – as the scale used is far more straightforward. The speed – the duration for which the shutter is open – is measured in fractions of a second. A 1/1000 sec shutter speed lets through half as much light (all other things being the same) as a 1/500 sec setting.

The shutter speed range is much more extensive than that afforded by the aperture range on even the most expensive lenses. The top speed on many digital cameras is either 1/4000 sec or 1/8000 sec. The longest automatically set shutter speed is usually 30 seconds – allowing 17 or 18 more stops of light to reach the sensor (up to 250,000  times more light).

Use the Bulb mode setting and the shutter will remain open for as long as you keep the shutter release pressed, so can be stretched to whole minutes – or even hours.

Chances are you’ve figured this out already, even if you’re brand new to photography. But have you ever thought about how your camera shutter actually works to regulate the brightness of your photos?

Your camera’s shutter: so how does it actually work?

Shutter speed is one of those fundamental controls on our camera that we take for granted, but knowing how it works will give you the knowledge you need to start taking pictures with more authority. Our latest photography cheat sheets illustrate how each component of your camera’s shutter works in tandem.

Your camera’s shutter controls how long the sensor is exposed to light. It uses a pair of ‘curtains’ or blinds. One opens to start the exposure, and the other is closed to end it.

At slower shutter speeds, both curtains on your camera’s shutter are open for some of the exposure. At faster speeds (any speed above the ‘flash sync speed’ – 1/200sec on many models), the second curtain closes the opening as the first is still opening.

So your sensor is effectively exposed to the light through a moving slit. In our latest photography cheat sheets we’ve illustrated, first, how your camera shutter system uses its pair of curtains to expose an image through a moving slit; and in our second cheat sheet we’ve illustrated where each of the key components sit within your camera shutter, and how they work.

To view the larger version, simply click on the infographic or drag and drop it to your desktop.

Your camera's shutter: so how does it actually work? (free photography cheat sheet)

Cheat Sheet Friday: how a camera shutter works

PAGE 1: Your camera’s shutter – so how does it actually work?
PAGE 2: Understanding shutter speed and camera shake
PAGE 3: How to check and set your shutter speed


Using shutter speed creatively: how to take control of your shutter for ultra-cool effects
10 common camera mistakes every photographer makes
10 common exposure problems every photographer faces (and how to fix them)
What your camera captures at every lens’ focal length (free cheat sheet)