Exposure, brightness, contrast, ... adjustments are camera specific and are provided by the camera drivers or the camera configuration web interface. ContaCam just shows what is given by the camera manufacturer.

brightness_usb.jpgFor USB camera / capture card

Go to Camera Advanced Settings - General Tab and press the General Settings button to display the driver provided dialog.
Note: some drivers do not store the set values; ContaCam can do nothing about that, please contact your camera / capture card maker.

brightness_ip.jpgFor IP camera

Go to its web interface (accessed through http://camera_ip_address from your web browser).