Lens Mount Adapter K&F Kf06.104 for Fujifilm X to M39 (M-39) Manual Aperture Compatibility

The K&F Kf06.104 lens mount adapter enables the use of M39 (M-39) screw-mount lenses on Fujifilm X-mount mirrorless cameras. This mechanical adapter provides a secure physical connection between the lens and camera body while maintaining correct flange distance for infinity focus. There is no electronic communication or aperture actuation through the adapter, so focusing and aperture adjustments are performed directly on the lens. The adapter is intended for photographers who wish to use vintage or manual M39 lenses on modern Fujifilm X bodies.

Advantages

The adapter preserves infinity focus and ensures stable mechanical coupling between M39 lenses and Fujifilm X cameras. Its simple, all-mechanical design makes it durable and lightweight, with no need for firmware or power. By allowing the use of manual-aperture lenses, the adapter expands creative options for portrait, street, and experimental photography on mirrorless systems.

Suitable for

• Photographers using vintage M39 screw-mount lenses on Fujifilm X mirrorless cameras
• Portrait and street photography with manual-focus lenses
• Experimental and creative applications where manual aperture control is preferred

Key specifications

• Mount conversion: M39 (M-39) screw mount to Fujifilm X-mount
• Connection type: mechanical only, no electronic contacts
• Focus: manual focus supported; infinity focus preserved
• Aperture control: manual aperture on lens required
• Compatibility: designed for mirrorless Fujifilm X bodies and M39 lenses
• Construction: lightweight metal alloy body for secure attachment

How to use

Attach the M39 lens to the adapter by screwing the lens onto the adapter's threaded mount until secure. Then align the adapter to the Fujifilm X camera mount and rotate to lock the adapter in place according to the camera's bayonet mechanism. Set the lens aperture and focus manually on the lens. Use the camera in manual or aperture-priority modes as appropriate and verify focus using live view or focus peaking if available. Because there is no electronic communication, exposure metering and EXIF recording of lens data are limited by the camera's capabilities.

Usage recommendations

For best results, check lens flange cleanliness and ensure the adapter and lens threads are free of debris before mounting. Use manual focus aids such as focus peaking or magnified live view on Fujifilm X cameras to achieve accurate focus. When working in bright conditions, consider using a lens hood or shading to reduce flare from older lenses that may lack modern coatings.