Originally posted by dnas I'm sorry, but this statement is absurd.
BEFORE micro 4/3, both Panasonic and Olympus had DSLR cameras with 4/3 sensors. The 4/3 sensors have the same size (4/3" image circle) as micro 4/3, and they also have the 4:3 ratio. (4/3 doesn't mean the ratio, it means the image circle size of 4/3") The Panasonic GH1 & GH2 have a sensor with ratio of 16:9 still within the 4/3" image circle.
Since both Panasonic and Olympus already had DSLR cameras with 4/3 sensors, saying that they went to micro 4/3 to reduce costs, in manufacturing 4/3 sensors, is absurd. So the advent of micro 4/3 was NOT to "reduce costs through sensor manufacture at a 4:3 ratio", because they already had a 4/3 sensors in cameras!!!!
In 2008, Panasonic and Olympus had 3.8% of the DSLR market share. In 2010 between them, they had 15% of the interchangeable lens camera market in Japan, while Sony had 8.2%. In 2010, 4/3 DSLRs made up less than 0.1% of this market segment.
It's clear that they didn't invent micro 4/3 to reduce sensor costs, but to produce a new product that had some chance of capturing a bigger market share. And they were successful!!!!!!!
Oly was doing very poorly with the 4/3 sensor size. It's IQ was not keeping up despite excellent Zuiko lenses. The whole point of smaller sensors was cost efficiency back when new market penetration relied on keeping costs down.
They've tried to leverage the sunk costs of M4/3 into a mirrorless system partnering with Panny on the fly. That's all. The sensor is still at a disadvantage for IQ and its cost advantage is almost non-existent.
In the short term being first to market with mirrorless has worked. In the long run they will be locked into a system with an inferior sensor compared to rivals who may come in with larger sensor and legitimately state "these,make better photos". Which horse do you want to bet on? Hint: This is not a sprint.
And the whole concept that mirrorless is cheaper does not seem to be deterring the "traditional" market from continuing to make entry-level mirror systems and selling well at price points lower than M4/3. Today Canon introduced yet another entry-level DSLR and one 2 steps above. Where's their mirrorless? The Canikon silence and patience is very interesting. They are not stupid companies and they have clearly sussed the mirrorless market and see issues with the PanOly approach. Also, the tepid reaction to Sony's NEX shows problems with entirely new lens mounts and aftermarket sales. PanOly may be a minor marketing success, but one with short legs.
The key for Pentax and Canikon may be to find a way to leverage existing users' lens arrays through backward compatibility. I expect these systems will NOT be "entry-level" at first because they will first go or higher-end users already vested in their respective systems. To do that they need sensors that match the IQ of the exiting lens investments by their user base. That's more likely to be APS-C than anything else, especially M4/3 because that means paying PanOly for rights as M4/3 is a closed system.
Also, M4/3 struggles with wider angle for many valid reasons stated elsewhere. The M4/3 sensors rate poorly at higher ISO's and in lower light. The body is cool, but the IQ is lacking. If you're in a marathon, you need lungs and legs for endurance, not printing. We shall see.
P.S. One very intersesting item is the buzz around Fuji's new beast for its fixed lens, retro feel, mirrrorless innovation, APS-C sensor, and, most importantly, its price point. People can blather on about market share, but margins are where it's at.