Olympus M.Zuiko Digital ED 12-40mm 1:2.8 PRO

The M.Zuiko Digital ED 12-40mm F2.8 is the first lens in Olympus's 'PRO' lens line for Micro Four Thirds, and designed to match the top-end OM-D E-M1. It offers a 24-80mm equivalent range, and is dust-, splash- and freeze-proof. It uses a focus clutch design similar to the 12mm F2 and 17mm F2.8 primes, so pulling the focus ring back towards the camera engages manual focus mode and reveals a distance scale. The lens also has a L.Fn button, whose function can be assigned from the camera.