This handy little pocket-sized! tool is essential for those precision shots that require exact depth of field settings and/or lens tilt & swing angles. Two calculators in one, the Rodenstock Depth-of-Field Calculator gives you the optimum f/stop more precisely than any of the tables or depth of field devices provided with some cameras. The Depth of Field Calculator can be used with all camera formats from 35mm up through 8 x 10". With the Lens Tilt & Swing Calculator, or Scheimpflug Calculator, you only have to focus your camera on two Scheimpflug points & set a few values on the calculator & it will provide the exact lens tilt/swing angle. Both calculators come with step-by-step, easy to follow instructions.