The Mamiya Leaf Sekor AF 55mm F2.8 LS D ($4,690) is a moderate wide-angle lens for use with Mamiya Leaf and Phase One medium format camera systems. When paired with a back with a full-frame 645 sensor, it covers about the same field of view as a 35mm lens on a full-frame camera, but it narrows to about 43mm when used with the Phase One IQ250 or Mamiya Leaf Credo 50. It's a solid option for any 645DF+ medium format system owner looking for a wide-angle lens. The lens is expensive, especially when compared with the Pentax SMC D 645 55mm F2.8 AL (IF) SDM AW that Pentax considers to be the standard-angle lens for its 645 digital system, but that lens omits a leaf shutter.

The 55mm is pretty compact when you consider the image circle it covers and its field of view. It measures 3.4 by 3.1 inches (HD), weighs about 1.3 pounds, and includes a reversible lens hood. It supports 72mm lens filters, has a big manual focus ring, and a clutch to switch between manual and autofocus operation. Its minimum focus distance is about 1.5 feet, which doesn't put it in macro territory, but does allow you to get fairly close to your subject. There's a printed depth-of-field scale with full-stop markings all the way down to the minimum f/22 aperture, and with distances printed in meters and feet.