The Canon EF 50mm f/1.2 L USM, (compare prices), is the current premium 50mm lens. It’s larger, faster, heavier and much more expensive than any of the other production lenses.

The Canon EF 50mm f/1.2L USM ($1,619 direct) is one of only two f/1.2 lenses available for the Canon EOS camera system, the other being the EF 85mm f/1.2L II USM, which is best suited for portraiture.

Canon EF 50mm f/1.2 USM L - Review / Test Report Lens Reviews - Canon EOS (APS-C. The Canon EF 50mm f/1.2 USM L is the brand new successor of the almost legendary EF 50mm f/1.0 USM L - the fastest mass production SLR lens ever.

This is a monster of a lens, and I think is the widest-aperture 50mm optic available for any of the major DSLR platforms. It's also incredibly well-constructed, as befits a Canon L-series lens.