The AE Lock is the <*> button at the back. It’s between the AF-ON and the focus point select buttons. AE stands Auto-Exposure.

Basically, the AE lock is for measuring the light, locking the measurement in the camera, recomposing the photo, and finally taking the photo.

  1. The AE lock works for only 4 seconds.
  2. The AE lock works every time the <*> is pushed in, overriding whatever happened before.
  3. The AE lock behaves differently depending on the mode:
    • In the evaluative metering, that’s the 63 zones metering. The AE lock will use mostly the point that is used for the focusing for measuring the light.
    • In the center-weighted average metering, that’s the whole viewfinder but the center is more important. The AE lock will use the center point for measuring the light.
    • In the partial metering, that’s the center of the viewfinder, just under 10% of the viewfinder. The AE lock will use the center point for measuring the light.
    • In the spot metering, that’s the small center of the viewfinder, just around 2% of the viewfinder. The AE lock will use the center point for measuring the light.
    • If the lens is in Manual Focus, the AE Lock will use the center point for measuring the light.