Pentax Lenses

Est. 1919 · Tokyo, Japan (Ricoh Imaging Company since 2011) · 47 lenses

Asahi Optical Joint Stock Co. was founded in November 1919 in the Toshima district of Tokyo, originally to produce spectacle lenses. By 1923 the company had begun supplying camera lenses to other Japanese manufacturers (including Konishiroku and the early Olympus), establishing itself as one of Japan's first specialist optical-glass workshops. The Asahiflex (1952) was Japan's first 35 mm single-lens reflex camera, and its successor — the Asahiflex IIB (1954) — introduced the instant-return mirror, a feature that would soon become standard across the SLR industry.

The Asahi Pentax (1957) gave the brand its enduring name, derived from 'PENTAprism' (the eye-level prism finder it inherited from Contax/East German tradition) and the bayonet-derived 'contAX' suffix. Pentax adopted the M42 'Praktica' screw mount and built up a wide lens line under the Takumar and later Super-Takumar / SMC Takumar names. The Spotmatic (1964) popularized through-the-lens (TTL) stop-down metering at consumer prices, and the SMC (Super Multi Coating) treatment introduced in 1971 set a multi-layer anti-reflection benchmark that influenced every coating program that followed.

In 1975, Pentax replaced the M42 screw mount with the K-mount bayonet — explicitly licensed as an open standard, with Ricoh, Chinon, Cosina, and others adopting it. The K-mount has remained mechanically and optically compatible across more than four decades, from the K1000 manual SLR (1976) through modern Pentax K-1 II full-frame DSLRs. The LX (1980) was Pentax's modular professional SLR, and the company was equally serious about medium format: the 6×7 (1969, modernized as the 67 II in 1998) and the autofocus 645 / 645N / 645D / 645Z (1984–2014) carried the Pentax name into the studio and landscape markets.

Asahi Optical Co. renamed itself Pentax Corporation in 2002. Hoya acquired Pentax in 2007, primarily for its medical-endoscope business, and in 2011 sold the imaging division to Ricoh — forming Ricoh Imaging Company, Ltd., while Hoya retained the medical-optics operations. Under Ricoh, Pentax has continued as a deliberately independent DSLR and medium-format brand: the K-3 III APS-C and K-1 II full-frame DSLRs, the Pentax 645Z medium-format DSLR, and the renowned DA Limited compact prime series (DA 21 mm, 40 mm, and 70 mm Limited) recognized for their all-metal barrels and distinct rendering character.

Notable designs: Super-Takumar 50mm f/1.4, SMC Takumar 35mm f/2, SMC Pentax-A* 85mm f/1.4, SMC Pentax-FA 31mm f/1.8 AL Limited, smc Pentax-DA 21mm f/3.2 AL Limited, HD Pentax-D FA* 50mm f/1.4 SDM AW

PENTAX 110 24mm f/2.8— 6 ELEMENTS / 5 GROUPS, f ≈ 24.0 mm, F/2.8 PENTAX 110 50mm f/2.8— 5 ELEMENTS / 5 GROUPS, f ≈ 50.0 mm, F/2.8 PENTAX 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 design PENTAX 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 FNO PENTAX DA 70mm f/2.4 Limited— 6 elements / 5 groups, 70 mm (scaled from patent f=67.74), f/2.4 nominal; patent FNO 1:2.5 PENTAX 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/2.8 PENTAX FA 31mm f/1.8 AL Limited— 9 ELEMENTS / 7 GROUPS, f ≈ 31.8 mm, F/1.8 PENTAX HD D FA 150-450mm f/4.5-5.6 ED DC AW— Marketed 150–450mm f/4.5–5.6, Design f = 153.50–440.00 mm, Design F/4.6–5.7 PENTAX 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 design PENTAX HD D FA 28-105mm f/3.5-5.6 ED DC WR— 15 ELEMENTS / 11 GROUPS, PATENT f = 28.70–102.38 mm, PATENT f/3.6–5.7 PENTAX HD D FA* 50mm f/1.4 SDM AW— 15 elements / 9 groups, f = 49.57 mm design, F1.45 design / F1.4 nominal PENTAX HD D FA* 70-200mm f/2.8 ED DC AW— 19 ELEMENTS / 15 GROUPS (PATENT), 19 ELEMENTS / 16 GROUPS (MARKETED), 70-200mm f/2.8 (MARKETED)PENTAX 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 marketed PENTAX HD D FA645 35mm f/3.5 AL [IF]— 10 PHYSICAL ELEMENTS / 8 PATENT GROUPS, PATENT DESIGN f = 36.000 mm, MODELED f/3.6 PENTAX HD D FA645 MACRO 90mm f/2.8 ED AW SR— 11 ELEMENTS / 9 GROUPS, f = 90.116 mm (DESIGN), F/2.85 (DESIGN)PENTAX HD DA 16-85mm f/3.5-5.6 ED DC WR— 16 ELEMENTS / 12 GROUPS, 16-85mm f/3.5-5.6 (marketing), 16.48-82.45mm, modeled f/3.565-5.776 (Example 1)PENTAX HD DA 18-50mm f/4-5.6 DC WR RE— 11 ELEMENTS / 8 GROUPS, 18-50mm F4-5.6, 0.3m MFD PENTAX HD DA 20-40mm f/2.8-4 ED Limited DC WR— 9 ELEMENTS / 8 GROUPS, 20–40mm f/2.8–4 (production), 20.60 / 30.00 / 39.00 mm (patent)PENTAX HD DA 55-300mm f/4.5-6.3 ED PLM WR RE— 14 ELEMENTS / 11 GROUPS, DESIGN f = 56.50–291.19 mm, DESIGN F/4.60–6.48 PENTAX HD DA* 11-18mm f/2.8 ED DC AW— 16 ELEMENTS / 11 GROUPS, 11–18 mm MARKETING / 11.25–17.70 mm DESIGN, F/2.8 CONSTANT PENTAX HD DA645 28-45mm f/4.5 ED AW SR— 17 PHYSICAL LENSES / 12 GROUPS, 28-45mm f/4.5 MARKETED, 28.699-43.874mm DESIGN PENTAX SMC 67 MACRO 100mm f/4— 6 elements / 4 groups, f = 99.97 mm, F/4 PENTAX SMC A 645 45mm f/2.8— 45mm f/2.8, 9 elements / 8 groups, 76° on 645 film PENTAX SMC A ZOOM 35-70mm f/4— 7 ELEMENTS / 7 GROUPS, 35-70mm f/4 (MARKETED), 36-68.5mm f/4.1 (PATENT)PENTAX SMC A* 135mm f/1.8— 7 elements / 6 groups, f = 134.99 mm, F/1.8 PENTAX SMC A* 200mm f/4 MACRO ED— 10 elements / 9 groups, f = 199.98 mm design, F/4 PENTAX SMC D FA645 25mm f/4 AL [IF] SDM AW— 12 REFRACTIVE ELEMENTS / 7 MODELED GROUPS, f = 25.6946 mm (DESIGN), F/4.1 (DESIGN)PENTAX SMC DA 16-45mm f/4 ED AL— 13 ELEMENTS / 10 GROUPS, 16-45 mm f/4 MARKETING, 16.30-43.70 mm / F4.1 MODEL PENTAX SMC DA 17-70mm f/4 AL [IF] SDM— 17 ELEMENTS / 12 GROUPS, DESIGN 17.50–67.89 mm, F/4.1 MODELED PENTAX SMC DA 18-55mm f/3.5-5.6 AL— 12 ELEMENTS / 9 GROUPS, 18-55mm f/3.5-5.6 (marketing), Design f = 19.10-55.16 mm PENTAX SMC FA 100-300mm f/4.7-5.8— 11 ELEMENTS / 9 GROUPS, DESIGN f = 103.00–290.04 mm, DESIGN F/4.8–6.0 PENTAX SMC FA 20-35mm f/4 AL— 10 ELEMENTS / 8 GROUPS, DESIGN f = 20.60-34.01 mm, DESIGN F/4 PENTAX SMC FA 28-105mm f/4-5.6 POWER ZOOM— 13 ELEMENTS / 11 GROUPS, DESIGN f = 29.02–101.60 mm, DESIGN F/4.1–5.8 PENTAX SMC FA 28mm f/2.8 Soft— 5 elements / 5 groups, f = 28 mm, F/2.8 nominal; patent F.No. 1:2.9 PENTAX SMC FA 645 120mm f/4 Macro— 9 elements / 7 groups, 120 mm marketed; 123.09 mm patent EFL, F4 marketed; F3.8 patent design aperture PENTAX SMC FA J 75-300mm f/4.5-5.8 AL— 12 ELEMENTS / 10 GROUPS, DESIGN f = 77.25–289.96 mm, DESIGN F/4.6–6.2 PENTAX SMC FA* 28-70mm f/2.8 AL— 14 ELEMENTS / 11 GROUPS, DESIGN f = 29.00–68.00 mm, DESIGN F/2.8 PENTAX SMC FA* 300mm f/4.5 ED [IF]— 9 ELEMENTS / 7 GROUPS, DESIGN f = 300.06 mm, DESIGN F/4.5 PENTAX SMC FA* 80-200mm f/2.8 ED [IF]— 16 ELEMENTS / 13 GROUPS, DESIGN f = 81.63–196.00 mm, DESIGN F/2.8 PENTAX SUPER-TAKUMAR 135mm f/2.5— 5 ELEMENTS / 4 GROUPS, 135mm f/2.5 MARKETED, f = 134.498 mm MODELED PENTAX SUPER-TAKUMAR 28mm f/3.5— 7 ELEMENTS / 7 GROUPS, f = 28.000 mm, F/3.5 PENTAX SUPER-TAKUMAR 35mm f/2— 8 ELEMENTS / 7 GROUPS, f = 35.000 mm, f/2 PENTAX ULTRA-ACHROMATIC-TAKUMAR 85mm f/4.5— 5 ELEMENTS / 5 GROUPS, f = 85mm (PATENT f = 100mm × 0.85), F/4.5 PENTAX-02 STANDARD ZOOM 5-15mm f/2.8-4.5— 8 ELEMENTS / 7 PHYSICAL GROUPS, MARKETED 5-15mm f/2.8-4.5, DESIGN f = 5.139-14.825 mm; FNO = 2.8 / 3.7 / 4.6 PENTAX-06 TELEPHOTO ZOOM 15-45mm f/2.8— 14 ELEMENTS / 10 GROUPS, MARKETED 15-45mm f/2.8, DESIGN f = 15.50-44.04 mm; FNO = 2.9