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Black aluminium adapter ring 4.2cm diameter with M39 and M42 threads

Ruth's sister

Ruth's sister M39 to M42 Lens Adapter Ring 4.2cm

SKU CH-BD3Y-6B4WX

Adapts M39 screw-mount lenses to M42 camera bodies with a 4.2 cm aluminium ring

  • Adapt Leica L39 lenses to Pentax M42 bodies
  • 2 cm aluminium ring keeps setup lightweight
  • Black anodised finish resists wear during frequent changes
  • Stack with other adapters for wider mount compatibility
  • Precision threads ensure secure lens-to-body connection

M39 to M42 Lens Adapter Ring

This aluminium alloy adapter ring connects Leica L39 LTM lenses to Pentax M42 camera bodies. It suits photographers who own vintage screw-mount glass and want to use it on later M42-threaded equipment. The 4.2 cm diameter ring is machined for a precise fit and ships as a single unit without retail packaging.

Passive Construction and Handling

The adapter contains no electronics, moving parts or coatings that draw power or generate heat. Its black anodised aluminium body adds negligible mass to the lens stack and operates silently in any shooting environment. No thermal management or power supply is required for normal use.

Sustained Mechanical Reliability

Under continuous mounting cycles the aluminium threads resist cross-threading and maintain flange-distance accuracy. The ring tolerates repeated attachment to M42 bodies or secondary adapters without loosening, making it suitable for extended sessions or frequent lens changes.

Highlights

  • Adapt Leica L39 lenses to Pentax M42 bodies
  • 2 cm aluminium ring keeps setup lightweight
  • Black anodised finish resists wear during frequent changes
  • Stack with other adapters for wider mount compatibility
  • Precision threads ensure secure lens-to-body connection

Specifications

No published specifications for this item yet.

Questions about this item

How do I attach the 39mm-thread Leica LTM lens to the 42mm-thread Pentax body using this 4.2cm adapter ring?

Screw the lens into the adapter's 39mm side until it seats, then thread the adapter's 42mm side into the Pentax mount; the step people miss is tightening both joints firmly so the 1.65in ring does not work loose during handling.

Will the aluminium-alloy threads or the black finish wear out and need replacement?

The aluminium threads resist stripping under normal lens changes, and the anodised black finish does not flake; no scheduled replacement is required unless physical damage occurs.

At what point does the 4.2cm length cause vignetting or focus-shift on a Pentax body?

The 1.65in thickness adds minimal flange distance, so infinity focus is retained on Pentax M42 bodies; vignetting only appears with ultra-wide L39 lenses wider than the adapter's clear aperture.

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