How to Use gray cards to find white balance, exposures & more on a digital SLR camera

This fantastic, in-depth video dives into the gray card in probably every imaginable way that you could think using the Nikon D3 . Going over various different lighting it can be used for, custom white balance for preset manual, gray source point for white balance correction, accurate exposure in spot metering mode, and adjusting the camera's LCD display brightness, on top of a ton of information!