Massa adapter M42 to M39 threaded mount SB1703 — camera lens adapter

The Massa adapter M42 to M39 threaded mount SB1703 is a mechanical adapter that enables the use of M42 screw-mount lenses on equipment with an M39 threaded mount. Constructed from metal, the adapter provides a stable mechanical connection and precise alignment between lens and body, allowing photographers and technicians to adapt cameras, rangefinder bodies, microscopes or custom rigs that require M39 fittings while retaining the optical characteristics of M42 lenses.

Advantages

The adapter offers a robust metal construction that resists wear and maintains reliable thread engagement during repeated mounting and dismounting. Its precise machining ensures concentricity and correct flange spacing for straightforward lens installation. As a purely mechanical solution without optical elements, it preserves the original optical performance of the attached lens and adds minimal additional distance to the optical path.

Suitable for

• Mounting M42 screw-mount lenses on M39-bodied rangefinder cameras
• Adapting M42 lenses for use with microscopes or laboratory optics that accept M39 threads
• Custom camera rigs and DIY projects requiring M42-to-M39 compatibility
• Photographic technicians or hobbyists consolidating lens collections across different mounts

Key specifications

• Mount conversion: accepts M42 screw-mount lenses and provides M39 threaded interface
• Material: metal construction for durability and stable connection
• Type: mechanical adapter without optical elements
• Surface finish: machined metal surface for precise thread engagement
• Compatibility: designed to match standard M42 and M39 thread dimensions

How to use

Screw the adapter onto the rear of an M42 lens using the M42 internal thread, then mount the assembly onto the target device by threading the adapter into the M39 mount. Ensure threads are clean and free of debris before installation to prevent cross-threading. Hand-tighten to secure the connection; avoid excessive force. Confirm correct seating and alignment visually and, where available, check focus and exposure on the camera or optical instrument after mounting.

Usage recommendations

For repeatable, safe operation, store the adapter in a dry environment to avoid corrosion and protect threads with caps when not in use. When using on rangefinder cameras or optical instruments, verify flange distance and compatibility to ensure proper focusing; some combinations may require additional adjustment or focusing aids. Regularly inspect the threads and mating surfaces for wear and clean with appropriate tools to maintain reliable performance.