Pentax K infrared lenses.
7 lensesGood 6Maybe 1Bad 0
Use an adapter to mount these lenses to many mirrorless cameras.
Data credit: these ratings come from the remarkable research at irlensdb.com, a community-built resource that has tested and documented more infrared lenses than any other reference online. I have stripped the retailer links and reformatted the data, but the hard work of collecting it belongs to them.
Ratings describe how a lens behaves on an infrared-converted camera. A maybe lens is usually fine wide open and shows a hot spot as you stop down, so check the notes before you write one off.
Lenses (7)
smc PENTAX-FA 31mm F1.8 AL Limited
Good- Focal
- 31mm
- Aperture
- ƒ/1.8
- Filter
- ⌀58mm
- Weight
- 350 g
No hotspot.
smc PENTAX-DA 35mm F2.8 Limited Macro
Good- Focal
- 35mm
- Aperture
- ƒ/2.8
- Filter
- ⌀49mm
- Weight
- 215 g
My best lens on my converted Pentax K-7; good sharpness wide open; very sharp at ƒ/5.6 and above. Charles Kinghorn
smc PENTAX-FA 43mm F1.9 Limited
Good- Focal
- 43mm
- Aperture
- ƒ/1.9
- Filter
- ⌀49mm
- Weight
- 155 g
No hotspot.
smc PENTAX-M 50mm F1.7
Good- Focal
- 50mm
- Aperture
- ƒ/1.7
- Filter
- ⌀49mm
- Weight
- 185 g
No hotspot.
smc PENTAX-FA 77mm F1.8 Limited
Good- Focal
- 77mm
- Aperture
- ƒ/1.8
- Filter
- ⌀49mm
- Weight
- 270 g
Hotspot starts at f/11, but it’s usable up to f/22.
smc PENTAX-FA* 85mm F1.4 IF
Maybe- Focal
- 85mm
- Aperture
- ƒ/1.4
- Filter
- ⌀67mm
- Weight
- 620 g
Hotspot starts at f/8, but it’s usable up to f/22.
smc PENTAX-A* 135mm F1.8
Good- Focal
- 135mm
- Aperture
- ƒ/1.8
- Filter
- ⌀77mm
- Weight
- 865 g
No hotspot. (The same lens also appears in the sheet mislabeled as Nikon F mount with a conflicting “hotspot from f/8” note — this Pentax K row is the correctly-mounted one and takes precedence.)
Next step
Ready to shoot infrared on Pentax K?
Links to Kolari Vision are affiliate links: if you buy through them the site earns a commission at no extra cost to you. They are the shop my own conversions and filters came from, and the recommendation would be the same without the program — full disclosure.
Links to Kolari Vision are affiliate links: if you buy through them the site earns a commission at no extra cost to you. They are the shop my own conversions and filters came from, and the recommendation would be the same without the program — full disclosure.
Other full frame mounts
All mounts in the database →Related guides
Where this data comes from
These ratings are compiled from the community-maintained Infrared Lens Database, with contributor credits kept in the notes. Ratings are submitted by photographers using different conversions, so results vary by wavelength, aperture and individual lens copy — treat them as a strong starting point, not a guarantee. Retailer links from the source have been removed. If you have tested a lens, contribute your result back to the original database so everyone benefits.