Let me get this out of the way up front - I enjoy discussing this, but do not intend to offend anyone or come across as argumentative. I feel that discussion is a good way to learn, and to clarify one's own thinking. I don't expect to change anyone's mind, and I hope nobody takes my lack of excitement as a personal slight.
My co-worker has an olympus with the 4/3's sensor. The sensor is smaller than "full-frame." In fact, it is the same size as 110 cartridge film. Anyone remember 110 SLR's? While I can still buy 110 film at my local drugstore, the format didn't really survive even in cheapo P&S cameras.
My co-worker just received an adapter to mount Olympus SLR lenses to his body. He has nothing but raves for the handling of his manual focus Zuiko 50mm. He has many times expressed dissatisfaction with manual focusing on the 4/3's zooms, so this adapter is gold to him.
He replaced his original Evolt for a newer model with LiveView because manual focusing through the finder in less than ideal lighting was close to impossible. It was to the point he has been convinced manual focus is nigh impossible except for a select few humans, or his eyesight is abnormally impaired. We actually had an argument because he refused to believe I could manually focus a camera!?!
So, given his issues with a camera system that he otherwise has bought into hook, line, and sinker, I am less than excited about the whole 4/3's promise.
In addition, I don't see anything in the press releases mentioning M mounts or rangefinder lens compatibility. The possibility exists that an adapter may one day be available, whether from Olympus, Leica, Panasonic, or whoever. That would be great for anyone who buys into the micro-four/thirds system. But until it actually exists, I fail to see why anyone should act as if it was already in their hand. There is not even any official plans to do such a thing as yet, despite as much hype as possible for the as-yet unreleased system.
Given the history of 110 film, I find it highly unlikely that a digital 110 format such as Four/Thirds will somehow outlast APS-C designs. All the benefits of elminating the mirror will apply to a body no matter what sensor it uses.
The Four/Thirds sensor might be good, but so is every other sensor out there. There is no inherent advantage with that sensor, yet the small size is an inherent DISadvantage. Any argument suggesting that the reduced sensor size is somehow a quality benefit is marketing, not reality. No matter how good the lenses are, the images will be enlarged far enough to negate any technical triumph they represent. As long as the sensor is based on existing technology and not some alien tech from Roswell, it will suffer from having to be enlarged more than APS-C images.
Given that the depth of a modern SLR is the smallest dimension, I see no reason to expect a micro Four/Thirds body to shrink much. I'm just not buying this whole "super compact DSLR" concept until I actually see and hold one. The concepts are intriguing, but that's been the story of digital cameras since day one. As a very young technology, I honestly think it's too soon to mortgage the house and sell the kids thinking this thing will save the world, to use a bit of hyperbole.
As for me, I'd buy a much-used RD1 before this, if I was in the market for a digital RF. That body at least lets me use readily available lenses going back almost 100 years. And it's a known factor, warts and all.
But the people that buy ia micro-Four/Thirds and enjoy it will benefit to the extent they desire. And I hope they derive much satisfaction.
Again, I'm not a hater. My co-worker and I have discussed the 4/3's systems ad nauseum, so I have had plenty of time to think upon it. I'm not spouting knee-jerk digital-hating invective. Please forgive me if I have sinned 😀
First of all apologies if I came off hostile.
With the 4/3rds system you have to realise that the sensor IS full frame, because the lenses have been designed for it. Hence each lens performs as it was designed, at the focal length it was designed to be. One of the biggest advantages of the 4/3rds sensor is that it allows light projected by the lenses to hit the sensor at a nearly completely perpendicular angle which means that corner sharpness is as high as the center of the frame, and the image quality is consistent over the whole frame. At current with the EOS mount or the Nikon F mount and 35mm size sensors, this sort of uniform image quality isn't possible as the light projected by the lenses hits the edges of the sensor at a more acute angle, meaning that the sensor with its little "light wells" which is dead flat, can't completely pick up all the light that it should.
The outcome of the advantages of the 4/3rds sensor and it's lens advantages means that no matter which of the lenses I'm using, they're not only out-resolving the 10mp sensor on my E-3, but they're near technically perfect in terms of image quality. The center of the frame with my 12-60 swd is not much if any sharper than the very edges. The same can not be said with canon or nikon full frame lenses.
As for manual focussing, you haven't used an e-3 obviously. The finder in the e-3 is bigger than both the nikon d300 and the canon 40d, and the pentax k20d. It's also a decent bit brighter. I have no problems manually focussing with the 12-60 swd kit lens.
In a recent interview somewhere on the web with an olympus designer, the idea of adapting M mount lenses came up and he stated that while it hasn't been completely proven as of yet, there is no reason why it shouldn't work, and also that he hopes to make it happen.
It terms of size, from the sketch ups of the m4/3rds on the 4/3rds site, the cameras are at least half the size of the current e-420. There are mock up line drawings of the size of the cameras on there.
Simon from DPREVIEW has actually mentioned a few times that the contrast detect autofocus is MUCH faster and more efficient than anything we've seen before which leads me to believe he's seen some working prototypes. Also another fellow emailed the editor of one of the sites like "imaging resource", who replied back that he was currently signed to and NDA (silence agreement) but from what he'd seen, the new m4/3rd cameras looked "sexy".
I'd say either olympus or panasonic or both already have some working prototypes going around.
You have to realize that it's difficult to quantify 4/3rds strengths and reasons to use it until you've actually tried it yourself. When in use with my e-3 and literally any olympus lens, everything just comes together really well. I can count on that each file will be sharp, contrasty, with the right colors, the right tonality, the right skin tones. Things like the blue color of the sky really shine on my e-3, whereas my canon and nikon DSLRs before it struggled to get the blue in the right shade. I'm happy shooting the e-3 up to 1600iso and knowing I will be able to get a decent print out of it, but most of the time I only actually need to shoot at 1250 ISO because of the in body IS, which works with every lens including the fast primes available.
I think the main strength of the system is still the lenses, which to my eye have no rivals. I'm still waiting on some fast high quality primes, but for the first time I'm actually enjoying using zooms with the zuikos.