+0.00 mm
Space for the adapter
45.46 mm
M42 screw mount flange
45.46 mm
Pentax K flange
Verdict: No infinity focus — the M42 screw mount flange is 0.0 mm shorter than the body's, so an adapter would need corrective glass.
What to expect#
Adapters with an optical element exist for some combinations, but they reduce image quality. A glass-free adapter in this direction only works for macro/close focus.
M42 screw mount lenses you could adapt#
- Laowa 15mm F/4 Wide Angle Macro
- Pentax SMC Takumar 50mm f/1.4
- Pentax Super-Multi-Coated Takumar 400mm f/5.6
- Pentax Super-Takumar 50mm f/1.4
- Pentax Super-Takumar 55mm f/1.8
- Pentax smc Pentax Takumar 135mm f/2.5 (V2/43812)
- Tokina RMC Tokina 28mm f/2.8
- Tokina TELE-AUTO 135mm f/2.8
- Voigtländer Color-Ultron 50mm f/1.8
- Zeiss Carl Zeiss Jena 1Q Biotar 1:2 f=58mm T
- Zeiss Carl Zeiss Jena Biotar 58mm f/2
- Zeiss Carl Zeiss Jena Flektogon 20mm f/4
- Zeiss Carl Zeiss Jena Flektogon 35mm f/2.4
- Zeiss Carl Zeiss Jena Pancolar 50mm f/1.8
- Zeiss Carl Zeiss Jena Sonnar 135mm f/3.5
- Zeiss Carl Zeiss Jena Tessar 50mm f/2.8
- Zeiss Carl Zeiss Jena Triotar-v2 135mm f/4
Pentax K cameras#
- Ricoh Pentax KF 2022
- Ricoh Pentax K-3 Mark III 2021
- Pentax K-1 II 2018
- Ricoh Pentax KP 2017
- Ricoh Pentax K-1 2016
- Ricoh Pentax K-70 2016
- Ricoh Pentax K-3 II 2015
- Pentax K-3 2013
- Pentax K-50 2013
- Pentax K-01 2012
- Pentax K-5 II 2012
- Pentax K-30 2012
- Pentax K-5 IIs 2012
- Pentax K-5 2010
- Pentax K-r 2010
- Pentax K-x 2010
- Pentax K200D 2008
- Pentax K20D 2008
Other systems for M42 screw mount lenses#
Frequently asked questions#
Will M42 screw mount lenses autofocus on Pentax K?
This adapter direction is not practical.
Does a M42 screw mount to Pentax K adapter affect image quality?
Any adapter that restores infinity focus here needs a corrective lens, which typically lowers sharpness and adds a slight teleconverter effect.
Last updated October 03, 2026 · How we calculate · Sources