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Adapter compatibility · Arri (industry standard)Various

PL to M42 adapter compatibility

Mounting a PL (Positive Lock) lens on a M42 (Pentax / Praktica screw mount) body — the feasibility verdict, AF / IS / aperture-control / infinity-focus outcome, image-circle relationship, official and reputable third-party adapter SKUs, and the caveats worth knowing before you buy.

Verdict at a glance

Mechanical
MFno ISAp. ring

Mount specs

Lens side

PL (Positive Lock)

Flange distance
52 mm
Protocol
Mechanical only
Type
cinema

Body side

M42 (Pentax / Praktica screw mount)

Flange distance
45.46 mm
Protocol
Mechanical only
Type
legacy-SLR

Flange-distance gap the adapter fills: 6.54 mm (52 mm − 45.46 mm). That gap is what a mechanical adapter has to fill to hold the lens at its design distance from the sensor.

Flange-distance schematic. Two rails share a sensor plane on the right. The M42 body register measures 45.46 millimetres; the PL lens needs 52 millimetres. The orange region between their left edges is the 6.54 millimetre gap an adapter spans.Sensor planeM42 body · 45.46 mmPL lens · 52 mm+6.54 mm adapter
Both distances right-aligned to the sensor. The 6.54 mm gap between the M42 body register and the PL lens (orange) is exactly what a mechanical adapter fills to hold the lens at its design distance.

Adapter examples

  • generic mechanical adapter ring (multiple vendors)

Caveats

  • Mechanical adapter only — no electronic communication between PL (Positive Lock) lens and M42 (Pentax / Praktica screw mount) body.

Common questions

Will PL (Positive Lock) lenses autofocus on a M42 (Pentax / Praktica screw mount) body through an adapter?
Autofocus is not applicable to this pairing — the PL mount predates electronic AF, or the bodies in this family do not implement AF for adapted lenses.
Does in-lens image stabilization (IS / VR / OS) still work through a PL → M42 adapter?
Stabilisation is not applicable — PL lenses in this family do not ship with in-lens stabilisation, or the adapter pair predates the IS protocol entirely.
What's the most-recommended PL → M42 adapter?
No SKU in our curated catalogue covers PL → M42 yet. Adapter examples photographers commonly use include the generic mechanical adapter ring (multiple vendors). Pair compatibility is mostly mechanical, so any well-built adapter at the correct flange distance should work — pick on build quality and tripod-foot integration.

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