Shutter Speeds Technique

Photography derives from the words writing with light and a photo depends upon exposure of a light sensitive material. In a traditional cameras case the light sensitive material is film or in the latest digital cameras its a charge coupled device or CCD. The amount of light reaching the film or CCD is known as the exposure and this is controlled by two items on a camera - the aperture and shutter speed. The aperture is a variable hole in front of the lens that adjusts to let more or less light through and the shutter speed is a cover over the film or CCD that controls the length of time that the light reaches the film.

As well as their practical needs both can be used creatively in photography and in this technique we will take a more detailed look at shutter speeds. The shutter speeds of cameras can go from long exposures of 30 or more seconds to fast speeds of anything as short as 1/8000sec.

All cameras from the most basic point-and-shoot single use camera to the latest highly sophisticated digital SLRs have shutter speeds. The very basic compact models may have a fixed speed and theres nothing you can do with these. More advanced 35mm compact cameras have adjustable shutter speeds, but the speed is controlled automatically and you have no override. And then we go into the more sophisticated cameras such as the digital cameras and SLRs. With this type of camera you still have the automated control but also an override of some form to allow more creative use of the shutter speed. And its here where we can start to have fun.

By adjusting the shutter speed you can control the movement of the subject. A fast shutter speed will freeze the subject and a slow shutter speed will make it look blurred as the subject moves. You can also combine flash with a slow speed to get movement and blur all in the same shot. Lets look at the techniques one by one.

If you have no control over automatic exposure you can do a couple of things to help obtain a slow shutter speed. One is to use the slowest film you can find. In print film this is ISO100 but you can safely override the speed to ISO25 to fool the camera into increasing the exposure by two stops. If you dont have film speed override you can buy stickers to put over the cassette before you load it. Slide film is available in speeds down to ISO50. Again you can override this and set ISO25, but you must tell the lab to adjust processing to compensate.

Anther alternative is to place a neutral density filter over the lens. This is a grey filter that reduces the light value and doesnt affect the colour of the picture. You can buy them in 2x, 4x, 8x and 64x values.