Pentax 645 infrared lenses.
13 lensesGood 8Maybe 4Bad 1
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.
Zooms (4)
smc PENTAX-FA 645 Zoom 33-55mm F4.5 AL
Good- Focal
- 33-55mm
- Aperture
- ƒ/4.5
- Filter
- ⌀82mm
- Weight
- 585 g
Slight hot spot at ƒ/22, perfectly usable at all focal lengths
smc PENTAX-FA 645 45-85mm F4.5
Maybe- Focal
- 45-85mm
- Aperture
- ƒ/4.5
- Filter
- ⌀77mm
- Weight
- 880 g
Hot spot starts at ƒ/8; usable up to ƒ/22 at 85mm, ƒ/16 at 65-75mm, ƒ/11 at 45-55mm
smc PENTAX-FA 645 55-110mm F5.6
Good- Focal
- 55-110mm
- Aperture
- ƒ/5.6
- Filter
- ⌀82mm
- Weight
- 500 g
No hot spot
smc PENTAX-FA 645 80-160mm F4.5
Good- Focal
- 80-160mm
- Aperture
- ƒ/4.5
- Filter
- ⌀77mm
- Weight
- 1,018 g
No hot spot
Primes (9)
smc PENTAX-FA 645 35mm F3.5 AL \[IF\]
Maybe- Focal
- 35mm
- Aperture
- ƒ/3.5
- Filter
- ⌀82mm
- Weight
- 324 g
Hot spot starts at ƒ/8, usable up to ƒ/22 or ƒ/32 in very bright areas
HD PENTAX-D FA 645 35mm F3.5 AL \[IF\]
Good- Focal
- 35mm
- Aperture
- ƒ/3.5
- Filter
- ⌀82mm
- Weight
- 570 g
Hot spot starts at ƒ/11, usable up to ƒ/22
smc PENTAX-FA 645 45mm F2.8
Bad- Focal
- 45mm
- Aperture
- ƒ/2.8
- Filter
- ⌀67mm
- Weight
- 476 g
Hot spot starts at ƒ/5.6, usable up to ƒ/8
smc PENTAX-A 645 55mm F2.8
Good- Focal
- 55mm
- Aperture
- ƒ/2.8
- Filter
- ⌀58mm
- Weight
- 320 g
Slight hot spot at ƒ/22, perfectly usable
smc PENTAX-FA 645 75mm F2.8
Good- Focal
- 75mm
- Aperture
- ƒ/2.8
- Filter
- ⌀58mm
- Weight
- 215 g
Almost no hot spot
smc PENTAX-FA 645 120mm F4 Macro
Maybe- Focal
- 120mm
- Aperture
- ƒ/4
- Filter
- ⌀67mm
- Weight
- 735 g
Hot spot starts at ƒ/8, usable up to ƒ/22 in very bright areas
smc PENTAX 645 135mm F4 LS
Good- Focal
- 135mm
- Aperture
- ƒ/4
- Filter
- ⌀58mm
- Weight
- 470 g
No hot spot
smc PENTAX-FA 645 150mm F2.8 \[IF\]
Maybe- Focal
- 150mm
- Aperture
- ƒ/2.8
- Filter
- ⌀67mm
- Weight
- 500 g
Hot spot starts at ƒ/8, usable up to ƒ/16 in very bright areas
smc PENTAX-FA 645 200mm F4 \[IF\]
Good- Focal
- 200mm
- Aperture
- ƒ/4
- Filter
- ⌀58mm
- Weight
- 669 g
Hot spot starts at ƒ/11, usable up to ƒ/32
Next step
Ready to shoot infrared on Pentax 645?
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 medium format 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.