DAY 61

PHOTOGRAPHY 101

The Shutter and Light

DO THE MATH

The shutter controls the amount of light that that reaches the film or sensor by regulating the length of time the shutter is open.

The shutter speed is generally found on a dial on the top of the camera but may also be controlled by a button or wheel. The shutter speed is also displayed inside the viewfinder and/or in an LCD display on the camera, depending on the model.

Although the shutter speed is generally a fraction of a second (such as 1/60), for convenience’s sake, the “1/” portion of the fraction is generally assumed. So, if your shutter speed is displayed as 100, you can safely assume that it is set at 1/100^th of a second.

Shutter speeds range from B (Bulb) to about 1/1000^th of a second. The Bulb setting means that the shutter will be open for as long as you depress the shutter button. Sometimes this option is handy when you wish to capture special lighting effects, such as fireworks.

An important concept to remember is that when you double the amount of time the shutter is open, you allow twice as much light to enter the camera. When you half the amount of time the shutter is open, you allow half as much light to enter. For example, 1/125^th of a second shutter speed lets in twice as much light as 1/250^th of a second, and 1/500^th of a second lets in half as much light as 1/250^th of a second. —CWN