Canon Powershot as a webcam in Debian GNU/Linux

It is possible!

I did this with Canon Powershot A85, but this should also work at least with models: which the capture program supports.

Software needed and notes

I installed libptp, capture and ptpcanon which is a Canon specific implementation of ptpcam (which, of course, is included in libptp package).

I never figured out how ptpcam or ptpcanon should actually work, but with capture everything works just fine. After compiling capture I got funny error that told me there was something wrong with /usr/include/usb.h 
/usr/include/usb.h:117: error: extra semicolon in struct or union
specified
I only had to remove extra semicolons from /usr/include/usb.h to make it work.

Note that if you're going to use and compile libptp with ptpcam you propably have to modify configure script a little. Libptp is included in gphoto2 libraries, but I compiled and installed it anyway. Ptpcam may be useful if you have other cameras than Canons.

To modify the configure script find a line that looks like this: 
if test "$LIBUSB_VER" \< "0.1.8"; then
and replace it with 
if test "$LIBUSB_VER" \< "0.1.10"; then
or whatever you libusb version is. Note that there are bugs in the version 0.1.10 which may damage your camera so you should use a higher version, I have 0.1.10a.

In order to transfer files with ftp I recommend having ncftp installed. If you have your own apache server at your computer you could just use symbolic linking or for example file copying with update switch.

Using capture

I manually chmodded my usb device so that a normal user can use it. This could be done with a script. I also give starting commands manually in case there are any problems.

To start with capture 
inanna@nornen:~$ capture start
I use following settings in webcam-like use:
inanna@nornen:~$ capture "quality normal"
inanna@nornen:~$ capture "size small"
Then I call my script 
inanna@nornen:~$ ./skripta
Here is my rough script which takes care of taking pictures in 30 sec delay and sending them by ftp. 
#!/bin/bash
# Immodesign kuvaskripta

E=q
until [ "$v1" = "$E" ]

do
capture "capture kuva.jpg"
sleep 1
ncftpput -u user -p pass my.fancy.server / pic.jpg
sleep 29
#read var1 --- kind of useless
done

exit 0
The sole purprose of this script is to continue looping until I violently stop it with ^C. It could have been done more elegantly but this works for me.

This way you can have fun with your camera and use it for many kinds of applications such as watching birds, spying on neighbours etc. You also get much better picture quality than with some cheap webcam. There is also the advantage of discerning when the camera takes the picture so you can get ready with some fabulous pose. The only fault of this webcam system is the fact that batteries won't last for eternity, but for occasional use this works. This is perfect for the narcissistic type of people as well ;)

Hope this howto makes someones life easier.

Last updated 020805 by Pauliina Niemi
paanni@NO.utu.SPAM.fi