Controlling Flash Exposures
Click to explore flash exposure compensation.
Flash usually gives you very good exposures
but if you block a sensor, you can get odd results like this gross overexposure.
A typical flash
When using the flash, you can avoid burned out foreground subjects and other exposure problems by adjusting the flash's output, or using flash exposure lock.
Flash exposure compensation lets you manually adjust the amount of flash illuminating the subject without changing the camera's aperture or shutter speed. This is an ideal way to balance flash and natural light when using fill flash and to correctly expose scenes or subjects that are darker or lighter than normal (middle-gray). Flash exposure compensation can be set to a minus setting to make the main subject darker or to a plus setting to make it brighter. A setting on some cameras that automates this procedure is flash bracketing that takes a series of pictures at different flash intensities.
Here five photos have been taken with flash.
From left to right, flash exposure compensation reduced the flash exposure one stop from one image to the next.
You can use flash exposure compensation in conjunction with regular exposure compensation. Doing so lets you use regular exposure compensation to lighten or darken the background that's illuminated by ambient light, and use flash exposure compensation to lighten or darken the subject illuminated by
the flash. This is a powerful combination of exposure controls that let's you capture images just the way you want them.
In both images flash was used to photograph
the Cardinal flower. In the image on the far right, exposure compensation was set to -2 to darken the
A few cameras have flash exposure lock that works much like AE lock and is used to properly expose off-center subjects. To use it, you center the main subject and press the shutter button halfway down. The flash fires a preflash to determine the best exposure and then locks it so you can recompose the
image before pressing the shutter button the rest of the way down to take the picture.