The Rodenstock 100mm f/4 Apo-Sironar digital HR Lens is a telephoto large format lens specifically designed for use with 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 maximum image area of 37 x 49mm. The included Rollei Electronic #0 Shutter delivers precision exposure control with speeds ranging from 1/500 - 30 sec, plus B, and allows f/stop adjustments in as little as 1/10 increments. Aperture and shutter speed are controlled via a Rollei Lens Control unit (purchased separately).
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 Apo-Sironar digital HR 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 Apo-Sironar Digital HR, you can use digital backs with a pixel pitch smaller than 10µ.
This lens is recommended for use at apertures of f/5.6 - 8; you should primarily use your camera's movements to control the depth of field. Given its 100mm focal length (which allows plenty of space) and because it benefits from superior optical design without any needed concessions for an SLR camera's mirror box, this 100mm Sironar's commonly adapted for use with DSLR cameras as a specialist for portraiture and products. Its remarkable resolution can produce results impossible to achieve with an SLR system lens.