f5 AE-L/AF-L Button
Explanation: In this menu you can program the AE-L/AF-L button like the Fn button and the preview button but the choice of options is smaller:
- AE/AF lock (default): Holding the button will lock both exposure metering and autofocus
- AE lock only: Holding the button will lock exposure metering only
- AF lock: Holding the button will lock autofocus only.
- AE lock (Hold): Pressing the button once will lock the exposure until you press it a second time.
- AF-ON: The only option that you cannot assign to the Fn / Preview button – pressing the AE-L/AF-L button will then activate the autofocus.
Tips: I prefer „AE lock only“ instead of the default setting „AE/AF lock“ for exposure and autofocus. If your subject does not move the focus is already locked when pressing the shutter-release button halfway and you can lock exposure and autofocus independently if you change the function of this button to locking exposure only.
You may like the option AE lock (Hold) if you find it uncomfortable to keep the button pressed with your thumb.