Canon 550D instruction manual Using the Built-in Flash, Depth of Field PreviewN

f: Changing the Depth of Field

Using the Built-in Flash

To obtain a correct flash exposure, the flash output will be set automatically to match the set aperture (autoflash exposure). The shutter speed will be set automatically between 1/200 sec. - 30 sec. to suit the scene’s brightness.

In low light, the main subject is exposed with the automatic flash, and the background is exposed with a slow shutter speed set automatically. Both the subject and background look properly exposed (automatic slow-speed flash sync). If you are handholding the camera, keep it steady to prevent camera shake. Using a tripod is recommended.

If you do not want a slow shutter speed to be used, set the [7Custom Functions (C.Fn)] menu’s [Flash sync. speed in Av mode] to [1: 1/ 200-1/60 sec. auto] or [2: 1/200 sec. (fixed)] (p.192).

Depth of Field PreviewN

Press the depth-of-field preview button to stop down to the lens’s current aperture setting. You can then check the depth of field (range of acceptable focus) through the viewfinder.

The depth-of-field effect can be clearly seen on the Live View image as you change the aperture and press the depth-of-field preview button (p.112).

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