Under your thumb

	On the right side of the camera "under your thumb" are two buttons. The AE lock button (press to read and lock exposure, can be re-programmed) and the AF point selection button (press to select AF point, AF point selection can also be re-programmed).

Shooting mode

Button	Operation
	AE / FE Lock Press to trigger automatic exposure and lock the exposure for the next shot. Hold the button to lock the exposure for more than one shot. The exact function of this button can be programmed via custom function 4 (see below).
	AF point selection button Press to choose a single AF point, turn the main dial or the quick control dial to scroll around the available AF points. Alternatively you can also use the new multi-controller to select a point directly (press the selector for the center point). The exact function of this button can be programmed via custom function 13 (see below).

Play mode

Button	Operation
	Thumbnail index / reduce magnification If in single view play mode, pressing this button will switch to a 3 x 3 thumbnail index. If already magnified it will step back in magnification levels once.
	Magnify Press to magnify the current image, there are fifteen steps up to a maximum magnification of 10x. Use the quick control dial to pan around the image, press the direction switch button to change from horizontal to vertical panning. Note that it is possible to change image while maintaining magnification, just roll the main dial.

Shutter button / AE lock button function (C.Fn 4)

Most sports photographers will prefer to use setting 1 or 3 where you can control WHEN the camera AF executes, a simple press of your thumb will start AF, then you can fire off as many shots as you like (more quickly obviously) without the camera refocusing, plus you can manual focus once the AF has completed.

AF point selection method (C.Fn 13)

Personally I preferred setting 1 which allows you to simply press the multi-controller to select an AF point or press the the AF point selection button to return to auto AF selection mode.

Rear of camera controls

The control layout at the rear of the EOS 20D has undergone several important changes from the EOS 10D. Firstly there are now only four buttons to the left of the LCD monitor (direction switch no longer required thanks to the multi-controller), the Erase button has been sunken further into the body to make it less easy to knock, the power switch now doubles as a quick command dial lock and lastly the new the multi-controller (the small 'joystick' type button above the quick command dial) used for AF point selection, panning in magnify mode and WB shift.

Shooting mode

Button	Operation
	Enter / Leave the Menu The camera menu is described on the following pages of this review.
	Information Displays current camera settings / information (click here for an example).

Play mode

Button	Operation
	Enter / Leave the Menu The camera menu is described on the following pages of this review.
	Information Changes the play display mode: No information, brief information, detailed information and histogram.
	Jump mode Enters jump mode which allows you to skip through images by 9 frames forward or backward.
	Play Displays the last image shot (the last image on the card). The EOS 20D is a shooting priority camera, which means that no matter what is displayed on the rear LCD this will be canceled if any of the camera's photographic functions (example half-pressing the shutter release) are accessed.
	Erase Press to erase the current image, displays an OK / Cancel dialog. In play mode you also get the option to erase all images (except those protected).

Lens mount controls

	On the side of the lens mount are the final set of camera controls. First is the flash open button, a press of this (in the right mode) will pop-up the onboard flash. Next down is the lens release button and below this the depth of field preview button which stops the lens down to the indicated / selected aperture to give a preview of DOF in the viewfinder.