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 Thirds cameras came to an end after the introduction of the mirrorless Micro Four Thirds format. Discontinued models include: The Four Thirds lens mount is specified to be a bayonet type with a flange focal distance of 38.67 mm. There are currently around three dozen lenses for the Four Thirds System standard. Before announcing that it would stop production of Four Thirds lenses in early 2017, Olympus produced about 20 lenses for the Four Thirds System under their "Zuiko Digital" brand. They are divided into three grades — Standard, High Grade and Super High Grade. High Grade lenses have faster