04-13-2018 01:35 PM
You are supposed to use the regular SD cards. Actually for the 5D Mark III, you should use the CF card as the transfer rate is a lot higher for the CF card slot than the SD slot.
04-13-2018 06:31 PM
i've just bought a 64gb micro sd card with an adapter, but my 5d mklll won't even turn on when i insert the card on it...
is this a common problem??
Yes. It is not unusual for the adapter to be an impediment. The micro-SD cards should only be used in devices that use them directly, without the adapter.
04-14-2018 08:52 AM - edited 04-14-2018 08:56 AM
I have used Samsung MicroSD without any issue. But as already written, with 5DIII the SD card will give you a write speed of 21MB/s. If you overclock the memory bus you could get around 50MB/s, but your card may break.
With CF I have seen around 120MB/s with Komputerbay x1066.
If I were you I would install SD Formatter,use a card reader and format the card with SD Formatter first.