Pentax SMC Pentax 50mm f/1.2

What mount is the Pentax SMC Pentax 50mm f/1.2?

The Pentax SMC Pentax 50mm f/1.2 has a native Pentax K mount. Pentax K is the 1975 bayonet that replaced M42 while keeping its 45.46mm register, and it remains in use on Pentax DSLRs today. With a plain mechanical adapter it fits Sony E, Fuji X, MFT, Canon RF, Nikon Z, and L-mount bodies and keeps infinity focus.

• Pentax K mount lenses
• Pentax K to Sony E
• Pentax K to Fuji X
• Pentax K to MFT

How much is the Pentax SMC Pentax 50mm f/1.2 worth in 2026?

A used Pentax SMC Pentax 50mm f/1.2 typically sells for $300 to $800, with most clean working examples near $480. Basis: eBay sold listings and KEH, 2024-2025. This is an estimate, not an appraisal; condition, variant, and service history move the number.

• The vintage lens buying checklist

Does the Pentax SMC Pentax 50mm f/1.2 work on Sony E, Fuji X, and MFT?

Yes. Pentax K has a 45.46mm register and every mirrorless mount is shorter (16mm to 20mm), so a simple Pentax K adapter reaches infinity with no optics. On a full-frame body the Pentax SMC Pentax 50mm f/1.2 frames as a 50mm lens; on APS-C (1.5x) it frames like a 75mm, on Canon APS-C (1.6x) like a 80mm, and on Micro Four Thirds (2x) like a 100mm. Plain adapter ring. Because K keeps the 45.46mm M42 register, M42 lenses also mount on K bodies with a thin adapter and keep infinity.

• Adapt Pentax K to Sony E
• Adapt Pentax K to Fuji X
• Adapt Pentax K to MFT
• Adapt Pentax K to Canon RF
• Adapt Pentax K to Nikon Z
• Adapt Pentax K to L-mount

When was the Pentax SMC Pentax 50mm f/1.2 made?

Pentax made the SMC Pentax 50mm f/1.2 from 1975-1990s. It launched the same year as the Pentax K mount itself (1975).

What is the optical design of the Pentax SMC Pentax 50mm f/1.2?

The Pentax SMC Pentax 50mm f/1.2 uses 7 elements / 6 groups, Double Gauss. Double Gauss designs are near-symmetrical six- or seven-element formulas that support fast apertures with good correction; fast versions show glow from spherical aberration and swirl from mechanical vignetting wide open.

Which lenses are similar to the Pentax SMC Pentax 50mm f/1.2?

Close alternatives in the same focal class are the Nikon Nikkor 50mm f/1.2 AI-S (50mm f/1.2, $400 to $950), the Carl Zeiss Planar T* 50mm f/1.4 (C/Y) (50mm f/1.4, $120 to $420), and the Asahi Pentax Super-Takumar 50mm f/1.4 (50mm f/1.4, $80 to $400). The Carl Zeiss Planar T* 50mm f/1.4 (C/Y) and The Asahi Pentax Super-Takumar 50mm f/1.4 cost less on the used market.

• Pentax SMC Pentax 50mm f/1.2 vs Nikon Nikkor 50mm f/1.2 AI-S
• Pentax SMC Pentax 50mm f/1.2 vs Carl Zeiss Planar T* 50mm f/1.4 (C/Y)
• Pentax SMC Pentax 50mm f/1.2 vs Asahi Pentax Super-Takumar 50mm f/1.4