The Rodenstock 100mm f/4 Apo-Sironar digital HR Lens is a telephoto lens specifically designed for use with large format digital backs, which require a smaller image circle with extreme resolution, color correction, and maximum performance at a large aperture. This lens is recommended for use with backs having a 33 x 44mm maximum image area, and provides a view similar to that of a 79mm lens on a 35mm format camera. This HR Digaron-S is delivered in a standard type Copal #0 shutter.
In many cases, digital photography is superior to conventional photography if the desired end product is a printed image. To achieve this ideal, however, a much higher demand is made upon the image reproduction quality of the lens. This is because of a digital image chip's smaller area, which means finer details in a scene are squeezed into a smaller image recording area, as well as their sensitivity to color fringes.
But Rodenstock's digitally-specific lenses such as this HR Digaron-S provide image quality which allows the maximum capacity of a digital back to be realized. The lens utilizes every technological possibility to
get as close as possible to the absolute limits of diffraction-
determined resolution, even accounting for the properties and thickness of a CCD's protective glass. With the HR Digaron-S, you can use digital backs with a pixel pitch as small as 5µ.
This lens is recommended for use only at f/5.6; you should exclusively use your camera's movements to control the depth of field.