Exposure Compensation on a Canon EOS Rebel T3 Series Camera
When you set your Canon Rebel T3 or T3i to the P, Tv, Av, or A-DEP exposure modes, you can enjoy the benefits of autoexposure support but retain some control over the final exposure. If you think that the image the camera produced is too dark or too light, you can use a feature known as Exposure Compensation, which is sometimes also called EV Compensation. (The EV stands for exposure value.)
Whatever you call it, this feature enables you to tell the camera to produce a darker or lighter exposure than what its autoexposure mechanism thinks is appropriate. Best of all, this feature is probably one of the easiest on the camera to understand. Here’s all there is to it:
Exposure compensation is stated in EV values, as in +2.0 EV. Possible values range from +5.0 EV to -d5.0 EV.
Each full number on the EV scale represents an exposure shift of one full stop. In plain English, it means that if you change the Exposure Compensation setting from EV 0.0 to EV -1.0, the camera adjusts either the aperture or the shutter speed to allow half as much light into the camera as it would get at the current setting. If you instead raise the value to EV +1.0, the settings are adjusted to double the light.
A setting of EV 0.0 results in no exposure adjustment.
For a brighter image, you raise the EV value. The higher you go, the brighter the image becomes.
For a darker image, you lower the EV value. The picture becomes progressively darker with each step down the EV scale.
Exposure compensation is especially helpful when your subject is much lighter or darker than an average scene.
Sometimes you can cope with situations like this one by changing the Metering mode setting. Switching to Partial or Spot metering probably wouldn’t have helped in this case because the center of the frame was bright. In any case, it’s easier to simply adjust Exposure Compensation than to experiment with metering modes.
You can take several different roads to applying exposure compensation. However, note that the option you choose controls whether you can apply compensation values greater than +/-2.0. In most cases, the 2-stop range is more than enough; a setting beyond that is typically useful only for creating HDR (high dynamic range) images.