Thursday, July 9, 2009

what is shutter speed? (revisited)

In my post on aperture (revisited), I mentioned there are three ways to control the amount of light entering your camera. Today's lesson focuses on shutter speed. Aperture is, in layman's terms, the mechanism that controls how much light enters the camera. Shutter speed is how long the shutter stays open before it closes and the image is captured. Confused? Picture a window with shutters - the aperture setting is the window itself - a larger window lets in more light, and vice versa. Shutter speed would be the amount of time it takes for the shutters to close up the window.

The longer the amount of time the shutters stay open, the more light enters the camera.
The shorter the amount of time the shutters stay open, the less light enters the camera.

http://3.bp.blogspot.com/_mMHvIAd8RH0/SRvlQxROZ5I/AAAAAAAAAyw/MlJR9_6Qlbg/s400/ManMode_Display_Callouts.jpg

Here is a photo of my camera's control panel (courtesy of manmode) - the number in the green box is the shutter speed. While it only shows 100, shutter speed is measured in fractions of a second, so "100" really means 1/100th of a second.

So why is this important? Shutter speed is important to capturing motion in a photo. A slower (or longer) shutter speed lets in more light (good for low light situations) but any motion in your image will be blurry. Shorter (or faster) shutter speeds capture motion clearly and in focus. In practical terms: use a faster shutter speed when you are trying to capture your kids running around in the backyard, and use a slower shutter speed when you are trying to capture your kids running around but with some movement and blur in your image.

Quick note - my first photography instruction warned us against using a shutter speed lower than 1/60 without a tripod, otherwise you run the risk of camera shake. I have taken clear, camera shake-free photos at shutter speeds lower than 1/60 but you have to be REALLY still.

Here is an example of using a deliberately slow shutter speed to blur the movement of running water:


(shutter speed 1/15th of a second)

Readers, now that we've reviewed shutter speed, it's time to turn your camera mode to shutter priority and practice practice practice! Try using a slow shutter speed to capture blur and movement.

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