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paid for 12G, got 8G?

or what to do if your Canon 5D formats your 12G Compact Flash card down to 8G

the problem

The thing is, that the Canon 5D will happily read and write a 12G compact flash card (or maybe even a 16G one if I could afford to buy one of those). But if you try to format the thing in the camera, it'll partition it down to a nice neat 8G and you'll lose 33% of your expensive capacity. I daren't even show the thing to my 1Ds: who knows what that would do to it. As it's generally good practice to format the CF cards in situ, many people do that. Do it on one of these cameras and you'll be displeased with the results.

Canon fixed this in a firmware update about a year after it happened. I'll leave the page here anyway.

the cause

The problem is that the 5D sticks an 8G partition on the disk when you format it. That's 8 not 12. So there's the best part of 4G sitting there unused.

how to fix it

Clearly you need to either stretch that 8G partition to 12, or delete it and create a 12G partition. You can do neither on the 5D. So take the card out of the camera and plug it into a PC. Make sure you can see the card from Windows - if it's not then you're going nowhere fast. Make sure there are no images or anything else you want to keep on the card before you start: you're going to zap anything there.

The obvious thing is to sort it out in Disk Manager. Nice try, but it doesn't work: you can't, apparently, re-partition removable drives inside windows disk management utility. Instead you have to resort to the command line.

Run the diskpart utility

Type "diskpart" into that little "start search" box under the start button, and select "diskpart". You'll get a UAC dialog box at this point, but you can get rid of those without thinking after a few days with Vista.

A tiny but scary black window opens, pauses for a second, and displays the "DISKPART>" prompt. If you're not scared then you don' t know what this program can do to your disks if you type the wrong thing at it.

Select the "disk"

Ok, so it's a card not a disk, but that's the word they use. First take a look at all the disks your machine can see so you know what's what, and then select your CF card, as that's the disk you want to mess with:

1. Type "LIST DISK" and you'll get a list. Look for the CF card - it's the one with the 8G size.
2. Type "SELECT DISK #" where "#" is replaced by the number of the disk which is your card.
3. Type "LIST DISK" again to confirm that you have selected the correct disk - it's indicated with a star.

Make sure you get the right disk - if you're not sure, then quit at this point.

Select the partition

1. Type "LIST PARTITION" and you'll get a list of the partitions on the CF card. Make sure you're looking at an 8G partition.
2. Type "SELECT PARTITION 1". Note that there should only be one partition to choose on your card.
3. Type "LIST PARTITION" again to confirm that you have selected the correct partition - it's indicated with a star.

Ok, so now you have selected the correct drive and the only partition on it, which is 8G in size. You're good to do the dangerous bit..

Clean that bad boy

This does really, really horrid things to the selected DISK and PARTITION, so you'd better have made the right choices above. Sure you're sure?

1. Type "CLEAN".

Create a new partition. a big one.

1. Type "CREATE PARTITION".

The defaults are for a big (12G) partition, so that's all you need.

Reformat the disk, in the PC

Type exit to leave the DISKPART program and get back to Windows. Then just open the computer window as normal and format the CF card. The result is a beautiful 12G card.

finally...

Try to remember to use "erase all" on the camera, not "format", as every time you do the latter, you'll have to repeat the above process.. until Canon crank their firmware version to deal with this.