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-----------------------------------------------------------------------
gPhoto FAQ (gphoto-devel@gphoto.org) http://www.gphoto.org/info.html
-----------------------------------------------------------------------
a. Will gPhoto run on my system, without GNOME installed?
b. Can gPhoto interoperate with other programs, like GIMP?
c. What hardware and operating systems will gPhoto compile and run on?
d. What libraries and system files does gPhoto require?
f. What is the current version of gPhoto?
g. How do I build and install gPhoto from CVS source?
h. I get ``Could not open camera''. How do I configure the serial port?
i. I get ``gphoto: error in loading shared libraries''
j. I get ``ld: cannot open -lgdk_imlib: No such file or directory''.
k. How do I use the gPhoto command line interface? How can I use it?
l. Who has developed gPhoto?
m. How do I write a gPhoto-supported plugin or new model interfaces?
n. How do I organize a HTML gallery theme?
o. What are the future plans for gPhoto?
p. Does gPhoto aim to be GNOME compliant?
q. Which digital camera should I buy? Which models do gPhoto support?
r. How do I take a picture and get a good result?
s. gPhoto is great! You could earn real money! But why is it *free*?
-----------------------------------------------------------------------
a. Will gPhoto run on my system, without GNOME installed?
Yes, at the moment gPhoto doesn't require gnome-libs.
b. Can gPhoto interoperate with other programs, like GIMP?
Yes, it will be able to spawn GIMP as an external editor. gPhoto saves
in all the image formats that imlib supports, e.g. JPEG, PNG, TIFF,
and GIF.
c. What hardware and operating systems will gPhoto compile and run on?
The preferred platform of the gPhoto developers is i586-pc-linux-gnu.
The gPhoto developers run Slackware 4.x, RedHat 5.x/6.0 & Debian 2.x.
We've had reports that gPhoto compiles and runs on the SuSE, FreeBSD,
NetBSD and also Sun's proprietary, non-free operating system Solaris.
d. What libraries and system files does gPhoto require?
gPhoto requires the following innstalled:
* The GNU C Compiler, the free compiler for the GNU system.
* GNU Utils (sed)
* GTK+ 1.0+
* ImageMagick 4.1+ (Not _needed_ but Imlib uses it)
* imlib 1.4+ (incl. libjpeg/libpng/libtiff/libz/libungif)
f. What is the current version of gPhoto?
The developer version is in GNOME CVS.
See http://www.gphoto.org/download.html for current info.
g. How do I build and install gPhoto from CVS source?
cd gphoto/
./autogen.sh
make
make install
h. I get ``Could not open camera''. How do I configure the serial port?
To those of you who get ``Could not open camera'', and your camera is
reported to work on the list (see http://www.gphoto.org/cameras.html),
please try this before you report it to <gphoto-devel@gphoto.org> as a
library bug:
Under Linux each serial port may have TWO names:
/dev/cua0
/dev/ttyS0
and
/dev/cua1
/dev/ttyS1
If you are using a serial mouse, it is probably on cua0 or ttyS0, so
you are probably connecting your camera to cua1 or ttyS1. /dev/ is the
correct serial port (ttyS0 or ttyS1).
[/root]# ls -l /dev/(serial_device)
Make sure your camera is connected to the correct port and turned on.
For now, you either need to be root to use gPhoto (because you need to
open a serial device) or you can create a ``serial_dev'' group in
/etc/group
(It's usually wise to backup /etc/group, just in case.)
[/root]# cp /etc/group /etc/group.old
If your user is john_doe, then add a new, unique entry in /etc/group:
[/root]# echo "serial_dev:x:234:john_doe" >> /etc/group
Make sure your new serial_dev group owns /dev/(serial_device)
[/root]# chgrp serial_dev /dev/(serial_device)
Give rw (read/write) permissions to the serial device to that group.
[/root]# chmod g+rw /dev/(serial_device)
If it still doesn't work, check the group permissions:
[/root]# ls -l /dev/ttyS0
[/root]# ls -l /dev/ttyS1
[/root]# ls -l /dev/(serial_device)
i. I get ``gphoto: error in loading shared libraries''
Make sure that you've got required/unique versions of libraries.
[/root]# ldconfig -v |grep imlib
[/root]# ldconfig -v |grep gtk
[/root]# ldconfig -v |grep imlib
j. I get ``ld: cannot open -lgdk_imlib: No such file or directory''.
Make sure that imlib is installed.
[/root]# ldconfig -v |grep imlib
libgdk_imlib.so.1 => libgdk_imlib.so.1.8.1
See http://www.labs.redhat.com/imlib/
k. How do I use the gPhoto command line interface? How can I use it?
After building the gPhoto binary, type ``gphoto -h'' for command-line
options. Here's the low-down:
Usage: gphoto [-h] [-n] [-s # filename] [-t # filename]
[-d #] [-l filename]
-n display the # of pictures
-s # filename save image # as filename
-t # filename save thumbnail # as filename
-d # delete image # from camera
-l filename save live preview as filename
-h display this help screen
Only catch is you MUST run gphoto in graphical mode to initially set
the camera library before running in command-line mode.
Web-cam example:
gphoto -l /home/httpd/html/livepic.jpg
A simple script set up can automate a lot of things (batch saving,
webcam, delete all pics, etc..) - please send in your scripts. :-)
l. Who has developed gPhoto?
See http://www.gphoto.org/team.html
m. How do I write a gPhoto-supported plugin or new model interfaces?
Scott updates the generic camera library docs - see ``PROGRAMMERS''.
It should be a snap for eager programmers to write gPhoto plugins, and
add support for more camera models, not supported by the great photopc
library (by Eugene Crosser), through the generic interface.
We would like to see more people contributing to the development.
Please send mail to camera manufacturers, see the CONTACTS file, and
encourage them to release free specs to software developers. You could
use the template LETTER file distributed with gPhoto.
Please send mail to <gphoto-devel@gphoto.org>, if you get negative
feedback, so we can warn people from buying cameras manufactured by
less consumer-friendly companies.
n. How do I organize a HTML gallery theme?
When a user selects to make an HTML gallery, they must first have the
index opened, and the images they want in the gallery selected. Then,
they type in the name of the gallery in a text entry, select a gallery
theme, and specify the output directory. It's possible to create your
own special code, customized to your own heart's desire.
See http://www.gphoto.org/themes.html for details.
o. What are the future plans for gPhoto?
gPhoto is being actively developed, and version 1.0 will have many new
features and support for more popular camera models.
p. Does gPhoto aim to be GNOME compliant?
Yes, but we will include a plain GTK+ version in the main archive.
ATM, gPhoto is not GNOME compliant, so it's not a real issue, yet.
If you want to make it GNOME compliant, please mail the gphoto
developers' list <gphoto-devel@gphoto.org> first.
q. Which digital camera should I buy? Which models do gPhoto support?
Probably the hardest decision you will have to make is which camera,
you will buy. While some expensive ones come with more resolution,
they do have tradeoffs. Most cameras are fantastic, making it a tough
decision to choose which camera to buy.
Kodak and Minolta both provide specifications openly for their cameras
meaning drivers for them can be written openly. Konica has recently
started work on a GPL application for *BSD and GNU/Linux which Phill
will incorporate into gPhoto extending the current Konica driver. It
is always a great help for potential camera customers to pressure
companies into support our work BEFORE you give them your money. Many
companies simply don't have time to look at the issues involved unless
there is an financial incentive to do so. The more open we can make
them, the better gPhoto can be and the more enjoyment you'll get from
your camera. The file ``CONTACTS'' contains a list of company members
who you can write to asking for GPL drivers or open specifications.
There is a sample letter in ``LETTER''. Please adjust it slightly
before sending it. 100 copies of one letter is not as persuasive as 25
different ones.
Please forward the feedback to <gphoto-devel@gphoto.org>, also if you
get a negative response.
OK, on with the show... In general, less expensive cameras are usually
much better suited for ``general'' purpose work. This is not to say
these cameras are not for professionals. It is simply to say that they
are better suited to the jobs where you need to get a high quality
snapshot, but don't need extremely high resolution prints. A good
example is using a camera for web pages photos, or for doing family
prints (5x7). For web pages, the 1024x768 size is a manageable size
which can be resampled to useable sizes (ie. 320x240, etc.) 1280x1024
would be overkill here. Also, the 1024x768 has proven to be more than
adequate to print photo quality 5x7 prints using a color printer.
Additionally, some cameras have a higher ISO equivalency (ISO 180),
which means they take better low light photos.
The expensive ones are more suited towards more sensitive work, where
the resolution makes perfect sense. The biggest advantage of the extra
resolution is that e.g. 1280x1024 is the perfect size to do high
quality 8x10 prints. Graphics professionals will also find the extra
resolution gives them more detail to work with. However, all this
extra resolution comes at a cost of having a lower ISO rating (ISO
100). Lighting needs to be more than adequate or you will have to
manual step up the exposure. While most photographers will find this
to be no impediment, if you are a casual user, or used to doing work
with a point-and-shoot camera, you will mostly likely be disappointed
with your indoor shots.
Unless you really need the resolution, the cheaper alternative make a
better choice for an all purpose high-end digital camera. The results
are very good, even at 8x10. However, if you are constantly doing 8x10
prints, or require a very detailed image, the expensive cameras are
probabaly your best shot.
The higher resolution of the images allows them to be cropped
substantially. The cropped images still have high enough resolution
for many purposes, and resolution superior to many other digital
cameras. The cropped images also are effectively made with a longer
focal length than if they were not cropped.
r. How do I take a picture and get a good result?
Three concepts that you should consider:
* Auto Focus - Even the best AF camera on the market (and we're not
going to start and argument as to who's is best) have limits...
Some are sensitive to the information in the frame, and need to
have vertical or horizontal lines (or both) to focus on. All (as
far as we know) have limitations on the minimum light level that
AF will work (and this is affected by actual light level as well
as the light reaching the AF sensors, which can be limited by
aperture.) That's why AF SLRs have a manual focus mode!
* Auto Exposure - All auto exposure systems need a reference. For
traditional film cameras, the metering is set to properly expose
an 18% gray. If you point even the best 35mm camera at a black
card, an 18% gray card and a white card, and let the AE do its
stuff, it will try to make the cards all look like 18% gray, and
all will come out looking about the same. If you do the same
thing, but use an incident light meter to set the exposure
(reading actual light levels rather than light reflected off of
the subject), then they will come out black, gray and white,
respectively.
* Blurry photos (not necessarily AF related) - It seems that most
of the blurry photos you see on the web are ambient light shots
(no flash). It is important to remember that digital cameras are
rated at a fairly slow ASA (ISO) equivalent.
s. gPhoto is great! You could earn real money! But why is it *free*?
gPhoto and everything you'll find in the archive comes under the GNU
General Public License (GPL), which means the entire contents of this
archive may be distributed freely - without any fees for profit or
not, as long as the source to this archive is made freely available to
the public. The contents of this archive may even be modified and then
re-distributed freely, but all derivative works also come under the
same License agreement as do the modifications made. Please see the
COPYING file in the source archive for a fully detailed description of
the GPL.
http://www.gnu.org/copyleft/gpl.html
Let's first thank Richard Stallman, who founded the GNU project in
1984, with the goal to create a complete and free operating system.
Also thanks to Linus Torvalds for starting work on his Linux Kernel
and making it available for all to use on standard cheap PC hardware.
Thanks a lot to Carsten ``Raster'' Haitzler for his work on the imlib
library, that gPhoto uses for many image operations.
Also thanks goes to the entire Kernel devel team, and the rest of the
free software community, and to those people who volunteerly work on
other useful GNOME applications, the GIMP and it's tool kit, GTK+.
http://www.gnu.org/
http://www.kernel.org/
http://www.gimp.org/
http://www.gtk.org/
|
