Camerctrls is a Neat Webcam Settings App for Linux
This free, open source utility puts a comprehensive suite of webcam controls at your control. The app is accessible though a clean GTK GUI or, if you roll that way, from a command line interface instead.
Something of simpler alternative to Guvcview (the ‘gold standard’ in open source webcam tools, imo), Cameratrls lets you configure almost every aspect of a webcam’s picture output, be it from a built-in potato cam or something fancier connected through USB.