Pentax's premium APS-C pancake — 61mm equiv at f/2.8 with HD coating and Limited-series quality.
The Pentax HD DA 40mm f/2.8 Limited was released approximately 2013 as an updated version of the classic SMC DA 40mm f/2.8 Limited, replacing the SMC coating with Pentax's newer HD (High Definition) coating. The Limited designation indicates Pentax's premium compact prime series with all-metal barrel and distinctive aesthetic. Pentax K mount.
f/2.8 maximum aperture. 40mm focal length (approximately 61mm equivalent on APS-C). HD coating (updated versus SMC). All-metal barrel construction. 49mm filter thread. At approximately 90g. Quick-shift focus (manual override over AF without engaging a switch). Pentax K mount.
The Limited series represents Pentax's premium compact primes, distinguished by all-metal construction, smooth focus rings, and distinctive industrial design. The HD coating improves flare and ghosting suppression versus the earlier SMC version. At 90g the 40mm f/2.8 Limited is among the lightest autofocus primes for any APS-C DSLR system. Quick-shift focus allows instant manual focus override over AF.
On the used market the Pentax HD DA 40mm f/2.8 Limited is an ultra-compact standard prime for Pentax APS-C DSLRs. Condition checks: metal barrel for dings or anodising wear, 49mm front element for marks, AF response and quick-shift focus engagement, aperture blade smoothness. The SMC DA 40mm f/2.8 Limited is the predecessor with the older SMC coating.