The Micro Four Thirds system is a revolutionary digital hybrid camera system which combines compact size, ease of use and movie mode functionality of the digital point and shoots with the larger sensor (and thus higher image quality and shallower depth of field) and interchangable lens capability of digital SLRs.
It achieves this by removing the mirror of the SLRs, and is only possible with the rapid technologic changes that have dramatically improved contrast detect AF functionality on par with entry level dSLR AF speed, while electronic viewfinder technology has also improved.
It’s short lens flange to sensor distance (20mm compared with 40mm on Olympus Four Thirds dSLR system) means that super wide angle lenses can be made much smaller (see the 7-14mm zooms here) and one can adapt almost ANY lens every made on it, including Leica M, Leica R, Olympus Pen, Olympus OM, Canon FD, Nikon F, Minolta, Pentax K, Hasselblad, Pentax 6×7, and even Canon EOS (although at present only at wide open aperture as EOS lenses do not have aperture rings).
The system is thus THE MOST ADAPTABLE camera system available in terms of lenses – however, they will generally only be able to be used in manual focus, and in 35mm terms, the sensor gives a 2x crop factor so that the angle of view of a 50mm lens will be similar to that of a 100mm on a 35mm film camera.
The Panasonic G series have the most functional visual manual focus assist system I have seen – it is automatically activated with most MFT or FT lenses by rotating the MF ring, but for other lenses just press the AF button on rear of camera. This makes MF accurate even in bright daylight or low light conditions.
The mirrorless digital cameras are really challenging the entry level dSLR market as they offer similar image quality and versatility in a smaller size (and in the case of Micro Four Thirds, much smaller lenses).
Until this generation of Micro Four Thirds cameras, the main complaint has been auto-focus speed – this has now been addressed at least for relatively stationary subjects to the point that Olympus claim their new E-P3 has the FASTEST AF of any camera with 3x kit lens to this point when going from a subject at 1m to a subject at infinity using their new lenses.
Indeed, the many changes Olympus has made with the E-P3 makes it a much more usable camera than any of its PEN predecessors and perhaps the first I personally would consider buying.
I personally own the older Panasonic GH-1 and this has now become my only camera I take on international travels (my Canon 1D Mark III dSLR and its heavy lenses are just too big to carry on flights) and it provides me with all I need. These new cameras have even better image quality and faster AF so should be adequate for most general photography needs if you choose the lenses to suit your needs.
The Micro Four Thirds cameras, although having smaller sensors than other mirrorless cameras such as the Sony NEX and Samsung, have sufficient image quality for most people while allowing smaller lenses, and indeed,have a much wider range of autofocus lenses and camera bodies available to choose from, with significantly better HD video (with the GH-2) and functionality.
A recent post in August 2011 by Mark Dubovoy on his 1st experience of using a GH-2 on an African safari along with a Leica S2 kit:
“I was surprised by how well thought out this camera is. Far superior to anything Canon or Nikon or Sony or Fuji have to offer. As complicated and feature laden as the camera is, the locations of the controls and the ergonomics (other than the traditional film type shape of the camera which is all wrong, but no manufacturer seems to want to deviate from) are excellent.”
He does not like an EVF nor the plastic feel but that’s part of the price to pay for this type of camera.
“The biggest advantage of the camera is that it is so light and small and the autofocus is very fast Image stabilization is also excellent and seems to be much better than the 35 mm crowd I have used 35 mm rigs in Africa before, and frankly, I did not miss them. As I mentioned above, the pro level bodies and lenses have gotten so big and so heavy that they have become quite a chore to use.”
He mainly used it as a telephoto using 14-140mm and 100-300mm lenses as the longest focal length on his Leica S2 is only 130mm in 35mm terms.