50 State Quarters to form what is known as a "mule". Only sixteen of these specimens, produced on dollar planchets, escaped from the mint. A 2005 Minnesota double die quarter, as well as a 2005 Minnesota quarter with extra trees (another die error), have both triggered numismatic interest. An unusual die break on some 2005 Kansas quarters created a humpback bison. Relatively more common are Kansas quarters bearing the motto "IN GOD WE RUST." The United States produces proof coinage in circulating base metal and, since 1992, in separately sold sets with the dimes, quarters, and half-dollars in silver. For the silver issues,
Micro Four Thirds system appropriate delay for shifting the focussing lens system are shorter, the smaller the focal length is. Micro Four Thirds has several advantages over larger format cameras and lenses: Though many DSLRs also have "live view" functionality, these function relatively poorly compared to a Micro Four Thirds electronic viewfinder (EVF), which has the following advantages: Olympus and Panasonic approached the implementation of electronic viewfinders in two ways: the built-in EVF, and the optional hotshoe add-on EVF. Until the introduction of the OM-D E-M5 in February, 2012, none of the Olympus designs included a built-in EVF. Olympus has four available add-on hotshoe