# Devices

Device specification is optional. Specifying a device allows automatic determination of point-spread functions, refinement of the correspondence between incident light and pixel values (e.g. power law), and refinement of certainty calculation.

    --device <d>      Set the capture device to <d>.

Available devices are as follows:

Available device types
canon_300d_raw_linear | Canon 300D (Digital Rebel) raw, linear data.
canon_300d_raw_linear+50mm_1.4 | Canon 300D with EF 50mm f/1.4 lens, unspecified aperture.
canon_300d_raw_linear+50mm_1.4@1.4 | Canon 300D with EF 50mm f/1.4 lens, aperture 1.4.
canon_300d_raw_linear+50mm_1.8 | Canon 300D with EF 50mm f/1.8 lens, unspecified aperture.
canon_300d_raw_linear+85mm_1.8 | Canon 300D with EF 85mm f/1.8 lens, unspecified aperture.
ov7620_raw_linear | OmniView OV7620 in raw RGB, linear mode.
xvp610_640x480 | IBM PC Camera Pro (XVP610) in 640x480 mode.
xvp610_320x240 | IBM PC Camera Pro (XVP610) in 320x240 mode.

These device options are described in more detail below.

Canon 300D (Digital Rebel)

Direct support for CRW files depends on the ImageMagick configuration, and may not be available on all platforms. Dave Coffin's dcraw program, invoked with arguments -d -4, will produce a raw, linear PPM file suitable for use with this device configuration. JPEG files produced by the 300D cannot be directly used as inputs for this configuration, since they are gamma-corrected rather than linear.

OV7620

Standard OV7620 drivers may not include options for setting raw RGB or linear modes. Linux users may apply a driver patch to access these modes. Setting the module option `rgb_raw=2` places the camera into the desired mode.

XVP610

Users of XVP610 cameras and Linux may wish to apply a driver patch. This version of ALE expects that this patch has been applied.