dov4l allows you to query and set the capabilities of a video4linux2 device. You can also set several parameters, such as brightness and contrast. It is a command line program that is especially meant for setting up a video4linux2 device before it is used with a Webcam grabber like grabby.
Grabby retrieves images from a video4linux or video4linux2 compatible Webcam or TV card. It can send them to an FTP server, can write them to disk, supports JPG and PPM, can auto-tune contrast/brightness, and lots more. It has tons of special effects. It also can display the effects in real time in a window or stream the result to a Web browser.