The Micro Four Thirds system (MFT or M4/3) is a standard released by Olympus and Panasonic in 2008, for the design and development of mirrorless interchangeable lens digital cameras, camcorders and lenses.

Comparison with other system

Compared to most digital SLRs, the Micro Four Thirds system (body and lenses) is smaller and lighter. However, their sensors are smaller than full-frame or even APS-C systems. As such, they may produce noisier/grainier images in low light conditions when compared with contemporary cameras with larger sensors. Unlike DSLRs, which use an optical viewfinder, Micro Four Thirds cameras use an electronic viewfinder. Resolutions and refresh speeds on these EVF displays were originally compared negatively to optical viewfinders, but today’s EVF systems are faster, brighter and much higher resolution than the original displays.

Sensor size and aspect ratio

The name of the system stems from the size of the image sensor used in the cameras, which is commonly referred to as a 4/3″ type or 4/3 type sensor.The Four Thirds system uses a 4:3 image aspect ratio, like compact digital cameras. In comparison, DSLRs usually adhere to the 3:2 aspect ratio of the traditional 35 mm format. Thus, “Four Thirds” refers to both the size and the aspect ratio of the sensor.

Advantages of Micro Four Thirds over DSLR cameras

  • Smaller and lighter
  • The absence of a mirror eliminates the need for an additional precision assembly, along with its “mirror slap” noise and resultant camera vibration/movement.
  • Viewfinders can be used when filming videos. In continuous mode (video takes continuous or sequential shots) the smaller sensor can be cooled better to avoid the increase of image noise.
  • The autofocus performance is the same for stills and videos, so the speed is much faster than conventional DSLRs in video mode. Because of the reduced sensor-flange distance, the sensor is easier to clean than with a DSLR, which also have delicate mirror mechanisms attached.
  • The smaller sensor size may allow for smaller and lighter telephoto-lens equivalents. Smaller and lighter cameras and lenses allow discretion and portability.
  • The smaller sensor size gives deeper depth-of-field for the same equivalent field of view and aperture. This can be desirable in some situations, such as landscape and macro shooting.
  • Electronic View

Source: Wikipedia