gPhoto2 is a free, redistributable, ready to use set of digital camera software applications for Unix-like systems, written by a whole team of dedicated volunteers around the world. It supports more than 1400 cameras
gtkam is the official GTK2 GUI for libgphoto2. Its purpose it to provide a standard client for libgphoto2 aimed at GNOME users. Consider it as a reference implementation for a graphical libgphoto2 client.
