Pentax K Lenses

20 interactive lens diagrams

Pentax K bayonet, introduced in 1975 | 35 mm film, APS-C digital, and full-frame digital

Pentax K replaced M42 screw mount with a bayonet while preserving a strong continuity ethos. Introduced in 1975, the mount has evolved through manual-aperture lenses, A-series electronic aperture information, autofocus KAF variants, digital APS-C DSLRs, and full-frame K-1 bodies.

The K mount is unusually adapter-friendly and backward-compatible compared with many camera systems, though features such as aperture control, autofocus drive, and electronic contacts vary by generation. Pentax's official M42 adapter also made the transition from screw mount less abrupt for photographers with existing Takumar lenses.

Its lens history includes compact Limited primes, rugged DA and D FA lenses, classic SMC coatings, and broad third-party support from the film era onward. K-mount pages are useful for comparing a long-running SLR bayonet that survived autofocus and digital without being abandoned.

Mount interface

Flange focal distance 45.46 mm, bayonet mount. 0° at 12 o'clock from the camera front; the lens-side view is the horizontal mirror. Dotted strokes mark photo-scaled or schematic (not-to-scale) dimensions.

Pentax K mount — camera-side front view (ka)Pentax K bayonet mount, camera-side front view. Flange focal distance 45.46 mm, nominal throat 44 mm. Profile pentax-k/ka.
Camera-side front
Pentax K mount — lens-side rear view (ka)Pentax K bayonet mount, lens-side rear view. Flange focal distance 45.46 mm, nominal throat 44 mm. Profile pentax-k/ka.
Lens-side rear
Throat / openingMount ringBayonet lug / slotLock pin / notchIndex markElectrical contactMechanical couplingScrews / sealsDatum & axis
LAOWA 15mm f/4 Wide Angle 1:1 Macro— 12 ELEMENTS / 9 GROUPS, f = 16.00 mm, F/4.1LAOWA 24mm f/14 2× Macro Probe— 27 ELEMENTS / 19 GROUPS, f ≈ 23.7 mm, F/14MINOLTA AF 28-75mm f/2.8 (D)— 28-75mm f/2.8, 16 elements / 14 groups, 4 hybrid aspherical surfacesPENTAX DA 21mm f/3.2 AL Limited— 8 elements / 5 groups, f = 21.60 mm design; 21 mm nominal, F3.2 marketed; F3.3 patent designPENTAX DA 35mm f/2.8 Macro Limited— 9 elements / 8 groups, 35 mm marketed; 34.41 mm patent EFL, f/2.8 marketed; 1:2.88 patent FNOPENTAX DA 70mm f/2.4 Limited— 6 elements / 5 groups, 70 mm (scaled from patent f=67.74), f/2.4 nominal; patent FNO 1:2.5PENTAX DA* 16-50mm f/2.8 ED AL[IF] SDM— 15 ELEMENTS / 12 GROUPS, f = 16.48–48.50 mm (2.94×), F/2.8 (constant)PENTAX DA* 50-135mm f/2.8 ED [IF] SDM— 18 ELEMENTS / 14 GROUPS, f = 51.5–131.0 mm (patent) / 50–135 mm (marketing), F/2.8 (constant)PENTAX F 85mm f/2.8 Soft— 5 ELEMENTS / 4 GROUPS, f ≈ 85.0 mm, F/2.8PENTAX FA 31mm f/1.8 AL Limited— 9 ELEMENTS / 7 GROUPS, f ≈ 31.8 mm, F/1.8PENTAX HD D FA 21mm f/2.4 ED Limited DC WR— 11 elements / 8 groups, f = 21.32 mm design, F2.4 nominal / F2.45 designPENTAX HD D FA* 50mm f/1.4 SDM AW— 15 elements / 9 groups, f = 49.57 mm design, F1.45 design / F1.4 nominalPENTAX HD D FA* 85mm f/1.4 ED SDM AW— 12 elements / 10 groups, f = 83.41 mm design; 85 mm marketed, F1.46 design; F1.4 marketedPENTAX SMC PENTAX-A★ 135mm f/1.8— 7 elements / 6 groups, f = 134.99 mm, F/1.8PENTAX SMC PENTAX-A★ 200mm f/4 MACRO ED— 10 elements / 9 groups, f = 199.98 mm design, F/4PENTAX SMC PENTAX-FA 28mm f/2.8 Soft— 5 elements / 5 groups, f = 28 mm, F/2.8 nominal; patent F.No. 1:2.9SIGMA 30mm f/1.4 DC HSM | Art— 9 elements / 8 groups, f = 30.785 mm design, F1.4 marketed / F1.46 designSIGMA 35mm f/1.4 DG HSM | Art— 13 elements / 11 groups, f = 35.16 mm design, F1.45 design / F1.4 marketedVOIGTLÄNDER APO-LANTHAR 180mm f/4 SL Close Focus— 9 ELEMENTS / 7 GROUPS, f ≈ 197.9 mm (patent) / 180 mm (marketed), F/4VOIGTLÄNDER MACRO APO-LANTHAR 125mm f/2.5 SL— 10 ELEMENTS / 9 GROUPS, f = 125.0 mm, F/2.5