Canon MARK III EOS-1 DS Instruction Manual page 34

Installing and Removing the Memory Card
The access lamp lights during any of the following operations: The
image is being exposed, being written to or read by the memory card,
being erased, or data is being transferred. While the access lamp is
lit, never do any of the following. Doing so may damage the image
data. It may also damage the memory card or camera.
• Opening the card slot cover.
• Removing the battery.
• Shaking or banging the camera around.
If the memory card already contains recorded images, the image number
might not start from 0001. (p.79)
Compared to other memory cards, hard disk-type cards are more
vulnerable to vibration and physical shock. If you use a such a card, be
careful not to subject the camera to vibration or physical shock especially
while recording or playing images.
When holding a hard disk-type card, always hold its sides. You may
damage the card by holding its flat surfaces.
Do not touch the SD card's contacts with your fingers or metal objects.
Even with the power switch set to <2>, when you insert or remove a
memory card, the access lamp might blink.
If a memory card-related error is displayed, see page 48.
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