Raspberry Pi A, User Manual, Page: 256 / 314

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H A R D W A R E H A C K I N G
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which are saved, by default, in the Joint Photographers Expert Group (JPEG) file format—the
same format used by most digital cameras and smartphones.
The software for the Raspberry Pi camera is run from the terminal or console. For best
results, run the software at the console without using the
startx
command to load the
graphical user interface (see Chapter 3, “Linux System Administration” for details).
The
raspistill
command accepts a number of optional arguments that control settings
such as the horizontal and vertical resolution of the captured image, the exposure mode of
the camera, the file type saved, and the level of compression applied to the final image. If
these options are left out of the command, defaults will be used.
To test the camera, simply run the
raspistill
application at the console by typing its
name as the command:
raspistill -o testcapture.jpg
This will show a five-second live preview (see Figure 15-7) during which time a red light on
the front of the camera will illuminate. This is an activity light, designed to provide confirma-
tion that the camera is working. If you wave your fingers in front of the camera during this
five-second period, you’ll see them appear in the preview window on-screen. When the five
seconds is up, the light will extinguish and the preview window will disappear.
Figure 15-7:
The
raspistill
capture
application
showing a live
preview image