Formatting a CompactFlash card to 2 Gb for a camera

30th March 2009

I have a Nikon Coolpix 4500 camera, which I use for all my specimen photography, and which serves me really well. The lens is good, which means I can actually make use of those 4 megapixels, in stark contrast to all those 12 megapixel camaras which are used to take photographs so blurry that maybe 10% of the nominal resolution carries any actual information. You should get one.

I bought it a few years ago, when a 128 Mb CompactFlash card was pretty big, and indeed it holds a little over a hundred photographs. That's probably enough for a single session if you're photographing family holidays and suchlike. But when I spend all day down in some museum basement photographing sauropod vertebrae in poor light, I often fill up the card. So I have to take my laptop with me just so I can dump the camera onto it and start again -- sometimes two or more times in a day.

So last week I bought a new and much bigger CompactFlash card for the camera. At the moment, 4 Gb seems to be the best price/capacity tradeoff point: I got 32 times my old card's capacity for �10, and felt stupid for not having done it ages ago.

Then I felt stupid again when I found that it didn't work. I put the new card in the camera and turned it on; the camera noted that the card was not formatted and offered to format it for me; I agreed, and it did so ... and then it claimed it was out of memory.

Some poking around on Google showed what the problem was : the FAT16 filesystem that this camera uses is not capable of addressing more then 2 Gb. When formatting the card, the camera built a filesystem that it couldn't read!

The solution was to put a 2 Gb filesystem on the card instead, which I was able to do after a little experimentation, on my Linux box. Here's what to do.

Put the 4 Gb card into the camera and let it format itself -- this step certainly doesn't hurt, and might just be necessary for some kind of low-level formatting.
Plug the camera into your computer's USB port, just as you do when transferring images. Turn it on.

Note what device the camera's card appears as in the mount list: for example, on my computer, df -m showed:

mike@xeno:~$ df -m
Filesystem           1M-blocks      Used Available Use% Mounted on
[...]
/dev/sdc1                 4096         1      4095   1% /media/disk

So the camera card was mounted from /dev/sdc1

Unmount the camera from the computer however you normally do this (e.g. by right-clicking on the camera's icon on your desktop and choosing the relevant menu item). However, leave it plugged in and switched on.
Format the card with a 2 Gb FAT16 filesystem as follows:
```
sudo mkdosfs -F 16 -n Camera2Gb /dev/sdc1 2097152
```
The number at the end specifies how many 1 Kb blocks you want: I specified 2^21, which gives 2 Gb in total. Note that you must subsitute your own device for /dev/sdc1 so that you put the new filesystem on the correct device.
You're done. Switch the camera off, unplug it, switch it on and start taking photos. I only have half as much memory as I paid for, but it's still 16 times as much as I had before, which is enough for something like 2000 photos. Should be enough for now!

Feedback to <mike@miketaylor.org.uk> is welcome!