The Rodenstock HR Digaron-W 90mm f5.6 lens specifically designed for use with digital cameras and digital backs, which require a smaller image circle with extreme resolution, colour correction, and maximum performance at a large aperture. This lens is recommended for use with backs as large as a 72 x 96mm maximum image area, and upon a 40 x 54mm back it will provide a view similar to that of a 58mm lens upon a 35mm format camera.

Rodenstock HR Digaron-W 90mm f5.6 specifications:
- Angle of view: 70°
- f-stop range: 5.6 - 45 (recommended 5.6 - 11)
- Image Circle: 125mm (Maximum format 72×96mm)
- Front filter thread: 67mm
- Push on Cap: 70mm
- Rear mount diameter: 51mm

The pixel size of the sensors of digital camera backs cannot be reduced just as one likes for achieving higher resolution with- out a significant increase of image noise and a reduction of exposure latitude. This is the reason why larger sensors with a resolution up to about 60 megapixels have been developed for professional digital backs. However, digital lenses with image circle diameters of about 70 mm designed for smaller sensors do not allow sufficient or even any camera movements. This is why the new Rodenstock lens series HR Digaron-W with larger image circles from 90 mm on and with an extremely high reso- lution very close to the physical limit of diffraction has been developed. This new lens series comprises the focal lengths of 40 mm, 50 mm, 70 mm and 90 mm. The last mentioned two lenses are the renamed former Apo-Sironar digital 70 mm f/5.6 and Apo-Sironar digital 90 mm f/5.6 which both had al- ready been calculated according to the much higher demands on freedom from aberrations for higher resolution with larger working apertures (reduced stopping down).