If the [Highlight tone priority] custom function setting is set to [Enable] on your camera, the Auto Lighting Optimizer setting is automatically canceled.

If you wish to enable the Auto Lighting Optimizer setting, change the [Highlight tone priority] setting to [Disable] first, and then set Auto Lighting Optimizer to [Enable].

For details on how to change the custom function settings and how to enable the Auto Lighting Optimizer setting, please see the instruction manual supplied with the camera.