Pentax smc Pentax-M 40mm f/2.8 - Pentax K Mount

This ultra-compact 'pancake' lens is one of the smallest optics ever produced for the Pentax K mount. Measuring just 18mm in length, it offers a 40mm focal length that provides a natural perspective, sitting comfortably between a wide-angle and a standard lens. It features a five-element design and is highly regarded for its portability when paired with M-series bodies like the MX or ME Super. When inspecting a used example, the extremely slim focusing ring should be checked for smooth travel, as it can occasionally become stiff with age. SDS technicians verify the five-blade aperture diaphragm for oil contamination and ensure the rear element is free from cleaning marks, which can be common on lenses that have been stored without caps. The optical elements are checked for the internal haze that can sometimes affect these compact M-series designs.