You can trim only the part of an image you need, or change the
composition of an image where an image shot horizontally becomes
vertical.
Also, when aspect ratio information is attached to an image shot with
EOS-1Ds Mark III or EOS-1D Mark III, the trimming range based on the
aspect ratio information is displayed.

Select the image to be trimmed.

Select the [Tools] menu [Start Trimming tool].

The trimming window appears.

When the image has redrawn itself, select a ratio and
drag the trimming range.

The trimming range can be moved by dragging.

You can enlarge or reduce the size of the trimming range by
dragging the four corners of the trimming range.

Cancel

Select a
trimming
ratio

Drag the
trimming
range

List of aspect ratios (width : height)

[Free]:

You can trim an image to any size, regardless of the
selectable ratio.

[Custom]: You can trim an image at the specified ratio.

Click the [OK] button to return to the main window.

The trimming range frame is displayed in the trimmed image

(p.106)

When the trimmed image is displayed in an edit window or the
edit image window, it is displayed in its trimmed form.

COP