Best fast prime lenses for Pentax K: Top Picks

Our catalogue lists 69 fast prime lenses for Pentax K. Fixed lenses with a maximum aperture of f/1.8 or wider, for low light and shallow depth of field.

How these were picked. Lenses are ranked using only data in our catalogue: those with editorial notes first, then those with a photo and a buying link, newer release years where known, and faster maximum apertures as a tie-breaker. This is a data-based shortlist, not a hands-on test ranking.

1. 

   1.Pentax smc FA 50mm F1.4

   50mm · f/1.4 · Pentax K

   A compact 50mm f/1.4 for Pentax K-mount that covers full frame. It weighs about 220 g and takes 49mm filters.

   Specs Buy on Amazon Compare with smc Pentax-FA 31mm f/1.8 AL Limited
2. 

   2.Pentax smc Pentax-FA 31mm f/1.8 AL Limited

   31mm · f/1.8 · Pentax K

   A celebrated wide-normal prime in Pentax's FA Limited trio. It covers full-frame film and digital.

   Specs Buy on Amazon Compare with HD Pentax-D FA* 50mm f/1.4 SDM AW
3. 

   3.Pentax HD Pentax-D FA* 50mm f/1.4 SDM AW

   50mm · f/1.4 · Pentax K

   A premium full-frame 50mm f/1.4 from Pentax's Star series. It has SDM autofocus, an all-weather build and weighs about 910 g.

   Specs Compare with 35mm f/1.4 DG HSM Art
4. 

   4.Sigma 35mm f/1.4 DG HSM Art

   35mm · f/1.4 · Pentax K

   A fast 35mm Art prime for full-frame, weighing about 665 g with 67mm filters. It was the first lens in Sigma's Art range.

   Specs Compare with smc Pentax-DA 50mm f/1.8
5. 5.Pentax smc Pentax-DA 50mm f/1.8

   50mm · f/1.8 · Pentax K

   A light 50mm prime for Pentax APS-C bodies, weighing about 122 g. It takes 52mm filters and focuses as close as 0.45 m.

   Specs Compare with HD Pentax-D FA* 85mm f/1.4 ED SDM AW
6. 6.Pentax HD Pentax-D FA* 85mm f/1.4 ED SDM AW

   85mm · f/1.4 · Pentax K

   A full-frame portrait prime in Pentax's star line with weather sealing and SDM focusing. It uses HD coating.

   Specs Compare with smc Pentax-FA 50mm f/1.4
7. 

   7.Pentax smc Pentax-FA 50mm f/1.4

   50mm · f/1.4 · Pentax K

   The Pentax smc Pentax-FA 50mm f/1.4 is a fast standard prime lens covering 50mm at f/1.4 for Pentax K mount cameras. The natural field of view suits street, documentary and everyday photography.

   Specs Buy on Amazon Compare with SMC Pentax-FA 77mm F1.8 Limited
8. 8.Pentax SMC Pentax-FA 77mm F1.8 Limited

   77mm · f/1.8 · Pentax K

   A short telephoto portrait prime in Pentax's FA Limited line. It covers full frame.

   Specs Compare with 14mm f/1.8 DG HSM Art
9. 

   9.Sigma 14mm f/1.8 DG HSM Art

   14mm · f/1.8 · Pentax K

   The Sigma 14mm f/1.8 DG HSM Art is a full-frame fast wide-angle prime lens covering 14mm at f/1.8 for Pentax K mount cameras, from the Sigma Art line with Hyper Sonic Motor autofocus. A wide-aperture wide-angle prime ...

   Specs Compare with smc Pentax-A 50mm f/1.4
10. 

    10.Pentax smc Pentax-A 50mm f/1.4

    50mm · f/1.4 · Pentax K

    Pentax smc Pentax-A 50mm f/1.4: a fast standard prime lens with a 50mm focal length and a maximum aperture of f/1.4, made for Pentax K mount cameras. The natural field of view suits street, documentary and everyday ph...

    Specs Compare with smc Pentax-A* 85mm f/1.4
11. 

    11.Pentax smc Pentax-A* 85mm f/1.4

    85mm · f/1.4 · Pentax K

    This 85mm f/1.4 fast short-telephoto prime lens from Pentax fits Pentax K mount cameras. The focal length is a classic choice for portraits and details.

    Specs Compare with smc Pentax-FA* 85mm f/1.4 [IF]
12. 

    12.Pentax smc Pentax-FA* 85mm f/1.4 [IF]

    85mm · f/1.4 · Pentax K

    This 85mm f/1.4 fast short-telephoto prime lens from Pentax fits Pentax K mount cameras. The focal length is a classic choice for portraits and details.

    Specs