Major thirds tuning tuning's simplicity and consistency are not shared by standard tuning, whose seventh-chord fingering is discussed at the end of this section. Each major-thirds tuning repeats its open-notes after every two strings, which results in two copies of the three open-strings' notes, each in a different octave. This repetition again simplifies the learning of chords and improvisation. This advantage is not shared by two popular regular-tunings, all-fourths and all-fifths tuning. Chord inversion is especially simple in major-thirds tuning. Chords are inverted simply by raising one or two notes three strings. The raised notes are played with the same finger as the
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.