Canon EOS-1 DX Mark III Advanced User's Manual page 455

Selecting ([ ]) Multiple Images to Erase Together
By adding checkmarks to the images to be erased, you can erase all those images at once.
1.
Select [
2.
Select [Select and erase images].
3.
Select an image.
: Erase images].
Turn the < > dial to select an image to erase, then press <
To select another image to be erased, repeat step 3.
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