Image: Rodenstock Rodagon lenses by Rodenstock, with focal lengths up to 135mm, have proven to be excellent high-resolution taking lenses for CCD cameras in combination with the Rodenstock focusing device Modular-Focus.

Image: Rodenstock Modular Focus

Rodagon lenses do not have a helical focusing facility. If these lenses are used as taking lenses, it is necessary to fit a focusing device. A Modular-Focus device was developed for this purpose. It has a stroke of 25 mm and offers high setting precision and stability. The straight-line guide guarantees that the lens does not rotate with the focusing ring.

SIZE (mm)
28 f/2.8 25 NA 0.58 -- 1.49
35 f/4.0 30 NA 0.24 -- 1.67
50 f/2.8 40 0.62 -- 1.12 0 -- 1.49
60 f/4.0 50 0.27 -- 1.14 0 -- 1.39
80 f/4.0 62 0 -- 0.96 0 -- 0.86
105 f/5.6 70 0 -- 0.71 0 -- 0.40
135 f/5.6 80 0 -- 0.35 0 -- 0.12

Image: Rodenstock

It takes a lens adapter, focus block, and camera adapter to couple a lens to a camera. The minimum path length of the above three items (LA) is 19.6mm for c-mount, and 21.6mm for f-mount. This distance may be increased by 25mm using the focus block expansion. Additional 25mm spacers may be required.

Rodenstock M72 x 0.75t Focus System
Image: Rodenstock

To accommodate the new larger format cameras with the larger non-standard mounting threads, an M72t mounting system is available.

An additional M72t camera adapter is available along with M72 Extension Tubes.

*Note the revised position of the Extension Tubes to clear the larger image beams.

For those cameras with a thread smaller than M72, a "step-up" ring must be used. These may be found at

The first number of the ring will be your camera thread, the second will be M72.

The wizard assumes a flange distance of 6.56mm, for an M72 mounting thread. If you procure a step-up ring for an M58 mounting thread, and the flange distance is 30mm, as an example, it will be necessary to remove one of the 25mm Extension Tubes to accommodate.