[lug] Linux Compatible Webcam

Daniel Webb lists at danielwebb.us
Thu Apr 21 17:24:35 MDT 2005

On Fri, Apr 22, 2005 at 03:58:51AM -0400, Ed Hill wrote:

> While you were trying, did you get any indication whether you were using
> the PTP or non-PTP mode?  Did you try both?  The reason I ask is that
> your model supposedly supports both a "native" (or non-PTP driver)
> along with a PTP mode driver:
>   gphoto2 --list-cameras | grep 'PowerShot A75'
>         "Canon PowerShot A75"
>         "Canon PowerShot A75 (PTP mode)"

That's a new driver since the last time I updated Debian testing (just
a few months ago).  So I apt-get'ed, and the new PTP mode driver works
great!  gphoto2 actually works correctly for the first time I've ever seen.
Very nice.  Only problem is that I still haven't figured out how to take
an image using gphoto2.  The Powershot A75 only talks on USB when in
view mode (not capture mode).  When I tried:

$ gphoto2 --camera="Canon PowerShot A75 (PTP mode)" --capture-image
Detected a 'Canon:PowerShot A75'.

*** Error ***
Error capturing image
ERROR: Could not capture.
*** Error (-1: 'Unspecified error') ***

For debugging messages, please use the --debug option.
Debugging messages may help finding a solution to your problem.
If you intend to send any error or debug messages to the gphoto
developer mailing list <gphoto-devel at lists.sourceforge.net>, please run
gphoto2 as follows:

    env LANG=C gphoto2 --debug --camera=Canon PowerShot A75 (PTP mode)

Please make sure there is sufficient quoting around the arguments.

I also tried switching to capture mode, then switching to view mode (so
that the lens was still out and open but I could view pictures, and then
trying, but when gphoto2 starts talking to the camera it shuts the lens.

> So its possible that you only tested the inferior of the two available
> drivers for that model.  But then, I'm an optimist.  ;-)

You were right in this case, at least mostly.  Everything except capture
works great with the new gphoto2 driver, and google comes to the
rescue for capture:


I haven't tried it, but they wrote a program to take time-lapse with the
A70, and have tested it on the A75!  So assuming it still works (last
updated this January), the two-month-belated answer to your question is:

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