The DSC Labs Fiddlehead / BackFocus Maxi Focus Pattern & Resolution Chart (40x24") is a chart designed for calibrating the focus on your video camera. Many video professionals consider calibration charts a necessity for optimizing camera performance and the production value of images. This chart has been designed with that philosophy in mind and works equally well in engineering or production work. This model has been designed with Stephen Lucas in Burbank. It features a decreasing radii spiral pattern that is designed to provide a visual pop at the precise point of optimum focus.