The M42 mount is a 42mm screw thread also known as the Pentax screw mount, the Praktica/Pentacon thread, and the universal screw mount. Lenses listed here fit M42 bodies from Pentax, Praktica, Zeiss Ikon, Chinon, Fujica, Mamiya, Ricoh, Yashica and others, and adapt easily to most modern mirrorless cameras.

These 8 M42 lenses are rated for infrared photography from real-world tests by IR photographers. Ratings are Good (8 lenses), Maybe (0 lenses), Bad (0 lenses), and Unknown (0 lenses) for hot spots, the bright spot some lenses leave in the center of an infrared image, and follow the thresholds below.

IR Focal
Length		 Minimum
Aperture		 Lens Filter Weight Notes Images
Good 20mm ƒ/4.5 SMC Takumar 20mm ƒ/4.5
 ⌀58mm 246 g Steve Forbes View images
Good 24mm ƒ/3.5 SMC Takumar 24mm ƒ/3.5
 ⌀58mm 243 g Steve Forbes View images
Good 28mm ƒ/3.5 SMC Takumar 28mm ƒ/3.5
KEH 		⌀49mm 212 g Steve Forbes View images
Good 35mm ƒ/2 SMC Takumar 35mm ƒ/2
 ⌀49mm 240 g Steve Forbes View images
Good 37mm ƒ/2.8 MIR-1b 37mm ƒ/2.8
 ⌀49mm      
Good 58mm ƒ/2 HELIOS 44M 58mm ƒ/2
 ⌀49mm   Report by Gus Potenza  
Good 100mm ƒ/2.8 Vivitar Auto 100mm ƒ/2.8
 ⌀52mm      
Good 100mm ƒ/2.8 TTArtisan 100mm ƒ/2.8
Adorama B&H		 ⌀49mm 307 g Soap bubble bokeh. Tested with 720nm and IR Chrome. MIRKOMX  

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What the ratings mean. Hot spots usually appear as you increase the lens ƒ-number, so each rating depends on the lowest ƒ-stop where a hot spot shows and how severe it is, and the thresholds differ by sensor format.

  • Good: No hot spots, or one that starts at ƒ/11 or higher where diffraction impacts image sharpness.
  • Maybe: Contains a mild hot spot that starts at ƒ/5.6 or ƒ/8 and is correctable in editing.
  • Bad: A hot spot that starts at ƒ/4 or lower, or is hard to correct in editing.
  • Unknown: No data reported.

How reports are checked and rated

M42 Lens Mount Adapters

Use an adapter to mount these lenses to many mirrorless cameras.

B&H - M42 lens mount adapters

Adorama - M42 lens mount adapters