Controlling digital SLR cameras with gPhoto2

Camera Settings

With the parameters --get-config and --set-config, you can have gPhoto2 read and set the camera settings. To learn which settings you can change for your camera, use the gphoto2 --list-config command to operate the unmounted camera. It provides a list of all the possible configuration parameters to choose from, although you probably wouldn't use most of them for a shot.

The values for sensitivity, aperture, and shutter speed are the most useful to avoid – for example, the infamous "brightness pump" of time-lapse photos. The first command below lists the settable ISO speeds and the current value.

$ gphoto2 --get-config /main/imgsettings/iso
$ gphoto2 --get-config /main/imgsettings/iso=2

The second command sets the third level (0, 1, 2) of ISO sensitivity. In the case of a Nikon D5100, that corresponds to ISO 160. You also can control aperture value and shutter speed (Table 2).

Cooperation

GPhoto2 works with various photography applications. Darktable lets you register for "tethering" and provides a highly convenient GUI for camera control, allowing you to configure your settings with mouse clicks instead of through the console. Gtkam also provides a GUI for gPhoto2, with which you can take shots directly from GIMP and edit them.

All these solutions have a handy feature in common. If the camera supports Live View mode, you'll see the image directly on your computer monitor. Because the images are typically larger than on the camera's monitor, gPhoto2 provides convenient focusing in critical situations, such as with a telescope or microscope.