bittermelon wrote:
Isn't the manual (for all cameras, and maybe for all electronics) online?
Yes, it is.
But enabling or disabling Back Button Focus (BBF) can be a little confusing.
In the factory default the AF-On button on the back of the camera is actually set up to provide BBF. When someone "sets up" BBF, they actually go into the control customizing screen and REMOVE autofocus from the shutter release button. So to "disable" BBF, they need to re-enable AF on that shutter release button. This is how it's done...
Go into the menu and navigate to the Yellow Wrench tab.
Navigate to C.Fn III Operation/Others (...)
Move down to item 4., Custom Controls.
There you will see graphical representation of all the camera controls you can modify.
The first item is the shutter release button. When that's highlighted in red, press the "Set" button.
This will display the three options that can be chosen: AF/Metering start, Metering only, Exposure Lock.
A camera that's set to BBF will have the center item, Metering Only, highlighted.
To re-enable standard focusing method, move to highlight the lefthand icon, AF/Metering start.
Press the "Set" button again and navigate back out of the menu.
This will re-establish AF start with half-press of the shutter release button (both metering and, when lenses have it, image stabilization will also start). You
also can press the AF-On button with your thumb to start AF, metering and IS.
The same procedure is used to enable BBF (remove AF start from shutter release button). Except the center "meter" icon is selected at C.Fn III, 4.
Page 498 to 500 of the manual cover the above (and more).
P.S. It also is possible to swap the function of the * button (AE Lock) and the AF-On button.