The Vello LENS-2020 Lens Calibration Tool sets up quickly onto a tripod through its 1/4"-20 tripod mounting socket and can level out using the two-way bubble level at the base of the target. With this tool, you can test your camera's auto focus accuracy and then calibrate the focus system to correct for any front-or back-focusing issues. After the adjustment is saved within the camera as a lens profile, it can be used for future photo sessions. The included gray card helps you to set custom white balance for true colors, and the target folds flat for easy storage and portability.