I built a camera around a 75mm lens and Sinar Graflok back. Made from 3/16" plywood, and a helicoid found on eBay. I use it with Grafmatic 4x5 backs, 6x12 Horseman back, and a Horseman 6x7 back. For wide angle of view I use the 4x5 or 6x12 backs, and for a normal angle of view the 6x7.