All you need to know about micro four thirds cameras
The Micro Four Thirds (MFT) system was invented by Olympus and Panasonic as a smaller alternative to their full-size Four-Thirds DSLR system but offering the same image quality, versatility and lens interchangeability.
Using the same sensors and processors as their Four-Thirds DSLR cousins, Micro four thirds cameras do without the focusing screen, mirror and prism assembly that provide the optical viewing system in a DSLR, and as a consequence are significantly more compact, and the lens-to-sensor distance reduced. This in turn enables the production of much smaller lenses.
The result is a true system camera that is the size of a large compact, but can be used with a variety of lenses and accessories, and produce DSLR quality images, as well as the ability to produce shallower depth of field than you can get with a compact. Users compose their pictures using the LCD screen only, or by attaching an optional clip on viewfinder.
Although only in their infancy, the system is predicted to become a major force in photography, offering as it does what many buyers see as the benefits of a DSLR in a compact-type package.
The target audience is both compact users wanting something more advanced but who don't want the bulk of a DSLR, as well as DSLR owners wanting something smaller to carry around every day.