Rodenstock Apo-Ronar 240mm f/9 — apochromatic large-format process lens in Copal shutter
Rodenstock is a German optical manufacturer with a long history of large-format process and photographic lenses. The 240mm f/9 corresponds to the Apo-Ronar series, an apochromatic process lens line used for large-format photography, copy work and graphic arts reproduction from the mid-20th century onward.
Apo-Ronar lenses are symmetrical, multi-element apochromatic designs mounted in a lens board rather than a camera bayonet, typically supplied in a Copal shutter for large-format cameras. The 240mm f/9 covers an image circle suited to 5x7in work with front movements. Element count, weight and filter thread are unconfirmed and omitted.
The apochromatic correction gives low colour fringing and flat-field sharpness across the image circle, making these lenses well regarded for product, architectural and copy photography where geometric accuracy matters more than shallow depth of field.
Apo-Ronar lenses remain in demand among large-format photographers. Buyers should check the shutter fires accurately at all speeds, confirm the iris blades are undamaged, and verify the lens board thread matches their camera before purchase.