Major thirds tuning also facilitate advanced guitarists' improvisation, precisely the aim of jazz guitarist Ralph Patt when he began popularizing major-thirds tuning between 1963 and 1964. In standard tuning, the successive open-strings mix two types of intervals, four perfect-fourths and the major third between the G and B strings: Only major thirds occur as open-string intervals for major-thirds tuning, which is also called ""major-third" tuning", ""all-thirds" tuning", and ""M3" tuning". A popular M3 tuning has the open strings in which the low G is a major third above the low E of standard tuning. Consequently, a seventh string for the low E is
Four Thirds system DSLRs. The smaller flange focal distance allows for more compact normal and wide angle lenses. It also facilitates the use, with an adapter, of lenses based on other mounting systems, including many manual focus lenses from the seventies and eighties. In particular, Four Thirds lenses can be used on Micro Four Thirds bodies with an adapter, however, "all of the functions of the Micro Four Thirds System may not always be available." Four Thirds system The Four Thirds System is a standard created by Olympus and Eastman Kodak for digital single-lens reflex camera (DSLR) and mirrorless camera design and development.