Pentax DA 40mm f2.8 XS smc

This ultra-thin 40mm prime lens (equivalent to 61mm in the 35mm format) measures a mere 9.2 millimeters in length and weighs just 52g. It’s maximum aperture of F2.8 produces sharp, bright images in a wide range of applications, including snapshots, scenic photos, portraits, and even incident-light indoor shooting. Nine rounded aperture blades produce extraordinarily smooth, natural bokeh. PENTAX Super Protect (SP) coating on the lens surface helps repel dust, water, and grease, making the lens easier to clean.  What's more, the exterior was designed by world famous designer Marc Newson.