The SMC Pentax-M 40mm f/2.8 is an iconic, ultra-compact "pancake" prime lens featuring a native Pentax K bayonet mount. Measuring just 18mm in depth and weighing under 110 grams, it is renowned as one of the thinnest 35mm full-frame SLR lenses ever produced. Engineered with Asahi's famed Super Multi-Coating (SMC) for high contrast, color fidelity, and effective flare control. Providing a versatile 40mm focal length—often considered a true "normal" perspective on 35mm film—it offers an ideal compromise between 35mm wide-angle and 50mm standard views for street, documentary, and everyday travel photography. Native to all Pentax K-mount 35mm film SLRs (ME Super, MX, K1000, LX, etc.) and digital SLRs (K-1, K-3, K-70), and easily adapted to modern mirrorless systems (Sony E, Fujifilm X, Micro Four Thirds, Canon RF). Serial number 5138511. Complete with a rear K-mount cap.

Overall Condition: Excellent

Optics are clear, fungus-free, and haze-free with a minor internal hair/filament, which will not affect image performance. The compact black metal lens barrel finish is in clean cosmetic condition with bright white front-ring lettering. Metal Pentax K bayonet mount and aperture coupling lever are bright and clean. Manual focus ring rotates smoothly, aperture ring clicks crisply at all stops, and aperture blades are oil-free and snappy. Serial number 5138511. Fully tested and working.

The SMC Pentax-M 40mm f/2.8 holds a special cult status among Pentax collectors and street photographers. Its ridiculously slim form factor transforms compact bodies like the Pentax ME Super or MX into practically pocketable 35mm setups. Due to its popularity with modern mirrorless camera adaptors and street photography enthusiasts, clean, scratch-free examples remain highly sought after on the secondary market.

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