Canon EOS-1 DX Mark III Advanced User's Manual page 740

Rec options
Set the recording method for still photos.
• Standard
Records still photos to the card selected in [
• Auto switch card
Same as [Standard], but additionally, the camera switches to the
other card when one card becomes full. When the camera switches
cards, a new folder is created.
• Rec. separately
Enables you to set a specific image quality for each card (
each shot, a still photo is recorded to card
specified image quality.
Note that recording separately to
for RAW images.
• Rec. to multiple
For each shot, a still photo is recorded to card
same image quality.
Caution
Maximum burst for [Rec. separately] is lower if you specify
different image sizes for cards and
740
Record/play].
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