After some nice entries on management, hiring, firing, nice photographs etc., it is time to get down to technichal detail again (yes, I have been programming today as well, maybe more about that later). So, if you don't use linux or are not in to digital photography with large RAW images, this post is not for you... See you next time ;-)

From my trip to Arizona I returned with a Canon Digital Rebel digital camera, which features exchangable lenses, SLR (the viewfinder looks through the lens with a mirror) and 6.3 mega pixels :-), and everything can be automatic or adjusted by hand. One thing I like about it especially, is that it is a photo camera: no diary, not games, no "boot up splash image", no movies. A very nice camera, even though I had to return it after two days because of a mechanical failure.

Since the images are large, I have a 512 MB compact flash card with it - I prefer to buy equipment that uses simple, cheap, industry standard components (as opposed to SD cards, Sony specific memory etc.). The camera is apparently supported under linux by gpoto2, but not by the version I have installed currently (SuSe 8.2) not wishing to install extra software (which would prove to be slow, given that the camera and my laptop support usb 1.0 only) I decided to get a compact flash reader for my laptop - which proved to be industry-standard cheap: 7 Euro and 50 cents at my local computer shop.

If you read the manual (pcmcia howto) carefully, it is easy. Of course I started reading after encountering problems. lsmod found pcmcia-core and ide-cs installed, which means pcmcia is installed, and there is an ide-hard drive attached to it. The compact flash card acts as a harddisk, which is nice. /var/log/messages.

cat /var/lib/pcmcia/stab
Socket 0: ATA/IDE Fixed Disk 
0       ide     ide-cs  0       hde     33      0

tells me the flash card is assigned to /dev/hde. Now I could mount it, if I had noted this line in the pcmcia howto:
A common error when using IDE drives is try to mount the wrong device file. Generally, you want to mount a partition of the device, not the entire device (i.e., /dev/hde1, not /dev/hde
instead, when doing

mount -t vfat /dev/hde  pcflash

I got the error 'wrong fs type bla bla bla'... After having found this in the manual it works flawlessly, doing

mount -t vfat /dev/hde1 pcflash

as usual with systems administration stuff, it is one small letter making a big difference. It seems that it is possible to mount it automatically as well using /etc/pcmcia/ something, I'll check that out later, now I want to do something with my pictures! (view them for instance...).

eat it RAW

Charles Vermeulen asked me innocently 'can your camera do RAW images', sure it can... RAW images are, unlike JPEG images, compressed without information loss (so-called 'lossless compression'), kind of like ZIP, but with meta-data about exposure, white-balance etc. The digital rebel spits them out, together with a small thumbnail (in JPEG) so you can see what the picture is about in your browser. Since there is no standard for RAW images, each manufacturer makes them differently.

Luckily, there is dcraw by Dave Coffin, which is reportedly faster and more accurate than the software provided by Canon (I am going to check that out, but the windows software for my Digital Ixus / Elph was so buggy it was hardly usable, so I find it believable for now). Dave's code is also used in commercial packages such as Photoshop.

Compiling dcraw is easy, just follow the instruction on the homepage, and one .c file leads to one executable. Dcraw transforms the raw image into PPM, which is universally read under linux.

Having GIMP (the GNU Image Manipulation Program, the open source equivalent of Photoshop) read RAW files was a bit more work. Again, basic instructions on how to use gimptool to create a plugin are on Dave's page. But, you must have installed the gimp development toolkit. SuSe provides packages for that through YAST, and after that, it is simple, although you have to run gimptool in a user's directory where you have used the GIMP before, otherwise gimptool doesn't know where to put the freshly created plugin.

And then, it just works, you can choose to use 4 colour RGB (whatever that is), use the camera's white balance or not (apparently just metadata) and some other options I do not yet understand.