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Next-Generation D-SLRs

New models deliver technology advances for photographers of every level

Micro Four Thirds
In 2003, Olympus introduced the first Four Thirds System D-SLR, featuring a smaller 4/3-type image sensor with a diagonal measurement of 21.63mm (half that of a 36x24mm 35mm film frame) and lenses designed specifically for that format. Benefits were touted to be improved image quality via the designed-for-digital lenses, an open design standard that meant any manufacturer’s Four Thirds lenses could be used with any manufacturer’s Four Thirds camera bodies and more compact cameras. This last item didn’t really pan out. While the Four Thirds sensor’s 2x focal-length factor effectively reduced lens size (the Olympus Digital Zuiko 300mm ƒ/2.8 frames just like a 600mm on a 35mm camera, but is much smaller and lighter and a stop faster than the 35mm format’s 600mm ƒ/4), most Four Thirds System D-SLR bodies were only marginally smaller than mainstream D-SLRs.

So, some five years later, we meet Micro Four Thirds. Based around the same 17.3x13mm image sensor, the Micro Four Thirds standard calls for a smaller lens mount diameter (by 6mm) and a reduced flange back length (the distance between the lens mount and the image plane) to reduce camera thickness considerably. Employing a Live-View electronic viewfinder rather than the conventional SLR prism and mirror assembly makes it possible to reduce flange-back distance to about one-half of that used in the Four Thirds System. There are also two additional signal contacts on the lens mount to facilitate future movie capability.

Existing Four Thirds System lenses can be used on Micro Four Thirds cameras via an adapter (possibly with the loss of some functions), but Micro Four Thirds lenses can’t be used on Four Thirds bodies. The three Four Thirds System aspect ratios (4:3, 3:2 and 16:9) have been retained.

The first Micro Four Thirds camera, Panasonic’s Lumix DMC-G1, measures a mere 4.9x3.3x1.8 inches, just 75% the volume of the next-smallest current D-SLR, the Four Thirds System Olympus E-420.

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