Arsenal Jupiter-8NB 50mm f/2

Arsenal Jupiter-8NB 50mm f/2

The Arsenal Jupiter-8NB 50mm f/2 was developed specifically for the Kiev-5 rangefinder. Unlike standard Contax/Kiev normal lenses, it does not use the camera's internal focusing bayonet. Instead, it mounts on the Kiev-5 external bayonet and incorporates its own focusing helicoid.

The focusing mechanism remains rangefinder coupled. A six-blade click-stopped iris provides settings from f/2 to f/22, and the lens focuses to approximately 0.9 metres.

Although the mount resembles the external bayonet used by other Contax-pattern cameras, the Kiev-5 geometry is different. Mechanical interference from the focusing barrel and locking components generally prevents normal use on earlier Contax and Kiev bodies.

Optical qualities

Rendering

The six-element, three-group construction belongs to the Jupiter-8 Sonnar family. It gives good central resolution at f/2 with softer edges and lower contrast in difficult light. Stopping down increases contrast and produces more even sharpness across the frame.

History

Development and Launch

The lens was introduced with the Kiev-5, whose redesigned lens mount omitted the traditional internal bayonet used by earlier Kiev rangefinders.

Production Evolution

Production continued into the early 1970s. Cosmetic details and engraving styles changed without creating a separate optical model.

Special Editions and Variants

Examples with different lettering styles belong to the same Jupiter-8NB profile.

Collector Notes

Compatibility should be listed specifically as Kiev-5 external bayonet. Do not classify the lens as a normal Contax RF external-bayonet lens.