Mamiya — Sekor Macro C 120mm f/4 A apochromatic macro lens for the 645 medium-format system
Mamiya's 645 medium-format system, launched in 1975 and expanded across decades of manual-focus and later autofocus bodies, includes a dedicated macro lens in its Sekor lineup: the Macro C 120mm f/4 A, an apochromatic design built for close-up work on 645 film bodies.
The lens offers 1:1 macro magnification to a 0.4m minimum focus distance, uses a 67mm filter thread, and is built from 9 elements in 8 groups, weighing approximately 745g. On 645 film its 120mm focal length is roughly equivalent to a 74mm f/2.5 lens in 35mm terms, resolving around 71 lines per millimetre at f/8.
The apochromatic correction keeps color fringing well controlled through the macro range, a genuine strength over non-apo macro lenses of the same era, while the longer focal length gives useful working distance for close-up subjects.
As a specialist lens for a still-active film format, clean copies hold value on the used medium-format market. Verify smooth helicoid travel through the macro range and check the aperture blades for oil contamination.