Major thirds tuning Major thirds tuning Among alternative tunings for guitar, a major-thirds tuning is a regular tuning in which each interval between successive open strings is a major third ("M3" in musical abbreviation). Other names for major-thirds tuning include major-third tuning, M3 tuning, all-thirds tuning, and augmented tuning. By definition, a major-third interval separates two notes that differ by exactly four semitones (one-third of the twelve-note octave). The Spanish guitar's tuning mixes four perfect fourths (five semitones) and one major-third, the latter occurring between the G and B strings: This tuning, which is used for acoustic and electric guitars, is called ""standard""
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.