How to Override Autoexposure with Exposure Compensation on Your Digital SLR
Exposure compensation (EC) is the ultimate autoexposure override on your dSLR. It can be a real problem-solver if a photo’s exposure doesn't come out the way you want it to.
Here’s how it works:
Review each photo after you take it and look to see how it's exposed.
You don't have to get too technical about it. Does someone's face need to be brighter? The photo’s underexposed; raise the exposure. Is the sky too bright? The photo’s overexposed; lower the exposure.
Press and hold your exposure compensation button while you dial in exposure compensation.
Choose positive EC to raise the exposure and brighten the scene.
Choose negative EC to lower the exposure and darken the photo.
Release the EC button and take another shot.
Review it to see if it's closer to what you want.
Exposure compensation stays locked in many cameras even after you turn them off, so be careful to reset EC to 0 after you've taken the shot.
Most cameras give you at least two stops of correction to work with. Some have as many as five! If you have to take that route, carefully review the exposure settings and make sure you can't set the aperture any wider and can't raise the ISO any more; recheck the metering mode to find out what’s happening to make the photos so far out of whack.