Canon EOS 5D MARK III Instruction Manual page 17

Selecting the Card for Recording and Playback
®_Standard
images will be recorded to the card selected with [Record/play].
_ Auto switch card
Same as with the [Standard] setting, but if the card becomes full,
the camera will automatically switch to the other card to record
images. When the camera switches to the other card, a new folder
will be created automatically.
®_ Rec. separately
You can set the image-recording quality for each card (p.119). Each
image is recorded to both the CF and SD cards at the image-
recording quality you have set. You can freely set the image-
recording quality to AI L and _, $3 and M _, etc.
®_ Rec. to multiple
Each image is recorded to both the CF and SD cards simultaneously
at the same image size. You can also select RAW+JPEG.
_[_ When [Rec. separately] is set, the maximum burst wil! decrease greatly
(p.121).
When [Rec. separately] or [Rec. to multiple] is set. the image will be
recorded under the same file number to both the CF and SD cards. Also. the
LCD panel wil! display the number of possible shots of the card having the
lower number. If one of the cards becomes full. [Card* full] will be displayed
and shooting will be disabled. If this happens, either replace the card or se[
the recording method to [Standard] or [Auto switch card] and select the
card with space remaining to continue shooting.
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