Canon: Evaluative Metering and One-Shot Af Mode

Everybody knows that by press the AE-Lock, you can lock the exposure. Isn’t it the purpose of the AE-Lock? Yes but…

Did you know that the AE-lock also happens automatically? It happens whenever you are in both:

1. Evaluative metering
2. One shot auto focus

The exposure lock happens at the time of the focus, on the focus point.

• This doesn’t only apply to the Canon 7D, but applies to almost all modern Canon dSLR.
• The exposure lock doesn’t happen automatically with any other exposure mode such as average, spot or partial metering.
• The exposure lock doesn’t happen automatically with the AI Servo focus mode.