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A short course in Photography cont...

Auto Exposure

The auto exposure (AE) works in conjunction with a light meter built into your camera. The meter will measure the available light and adjust the shutter speed according to the film speed. In low light the AE will leave the shutter open long enough to exposed the film properly. This is the miracle of modern camera technology. In the past you had to do all the calculations based on a hand held light meter. Notice the elements of exposure; film speed, shutter speed and aperture setting ( if available). These are all related to one another and are based on the available light coming into the lens. Change one of these elements and you most adjust the others acordanly.

Look at the inside of any film box. Here they offer you there best guess for manually setting your camera exposure without a meter. Pictures that are under exposed will turn out too dark and of course picture that are over exposed will be washed out. Exposure ( or the gathering of light onto the film ) has everything to to with how well the pictures will turn out. When you understand exposure settings you will understand how to take better pictures. At least in the technical sense, picture taken skill still requires practice. You can't obtain artistic photos without a good understanding of exposure either. As an artist paints with his brush a photographer paints with light.

The light meter in most automatic cameras is set to spot the available light in the center of the frame. Because our subject may not reside dead center, most automatic cameras have a AE/AF lock. This is accomplished by pointing the center of the view finder at a neutral spot at the same distance as the subject. The AE/AF lock normally works by depressing the shutter release button half way down. Once locked, you can then compose the shot by framing the subject and fully depressing the shutter release button. We're trying to avoid exposing to the bright sky or to a dark shaded area. Gray concrete ( not bright white ) or greenery are good neutral elements.

So how do you correctly set the exposure on your camera? Simple turn the auto flash off. The cameras AE will set the shutter speed correctly for the available light. Your only concern then is blurring the photo from a slow shutter speed. The shutter speed may be set too slow in low light conditions, if so, the camera will let you know by flashing a red light in the view finder. But wow! Now you're thinking before shooting and your thinking about light. To solve this set the camera on a tripod, or tabletop, and set the auto timer to take the picture. The camera can now take advantage of slower shutter speeds without blurring the photograph  from hand shake. In this setting the subject is required to remain still. Walla, a properly exposed available light photo that's sharp to boot.

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