I post this here in the Sony forum because the RX1 is for me a sign what to come.
Ok the Leica M fits the bill but is also out of reach for some of us. What are your thoughts about FF mirrorless cameras in 2013? I think Sony will likely make one. Canon or Nikon anyone?
So here's my hypothesis...
The question has little to do with the sensor. Sony obviously has the sensor technology well in hand, albeit at a price. There is certainly a market for cameras with 35mm format sensors, no matter how good or bad APS-C and FourThirds are, and Sony seemingly can build them into arbitrarily small bodies. Prices will come down somewhat with volume, as usual for electronics manufacture, so for them to produce bodies at an affordable price point (say $2000) is really a matter of putting in the investment, and then having a product that is acceptable for sale.
So the real issue of whether and how to make a mirrorless FF camera has to do with lenses, and the match between sensors and lenses. What we've seen so far is that, even with APS-C format, existing RF lens designs are often a troublesome match to the sensor. Only those cameras with sensors customized for short register mounts do well with a large enough range of the existing lenses. Customizing sensors for these lenses implies additional costs, and is not always perfect either. The required geometry for SLR lens designs, because of the moving mirror, makes a much easier adaptation to digital sensors. But SLR lenses are bulky, again because of the required geometry, which defeats much of the purpose for the mirrorless system.
So what's the solution? Well, we've seen three smaller-than-FF format solutions so far: Micro-FourThirds, NEX, and Fuji X (skipping the NX simply because it's not been a big seller, but it's a fourth). The best quality images from these three formats have all been made with lenses optimized for the format and sensor characteristics. mFT has been around long enough now for a fairly extensive lens line to be developed, and there are quite a few good lenses for it. NEX has been around a couple of years less, and the lens system is growing slowly. The Fuji is just out of the traps and the lens system is still quite immature but good quality.
For Sony to take on producing a mirrorless FF system that encompasses the desire for compact size and high quality will require, I believe, nothing less than a full bore lens development program with lenses optimized for the sensor and mount. There's certainly value in that, and there's a ready market for it if many of the comments made on the varlous new M threads are to be believed. BUT it's a very price conscious audience already: they know all about the Leica M, the value and quality of Leica (and Zeiss, and Voigtlander) lenses. They also know the price of these things, and many don't want to pay the ticket. And developing lenses is both very expensive and takes a lot of time.
The question comes down to how adroitly Sony (or any other manufacturer) can pilot their way between the development of bodies and lenses that can be sold profitably, at affordable prices, and yet fulfill the very high expectations of the buying community. The RX1 may be a test program ... Will people buy into a dedicated full frame camera with a super quality lens at this price level? The next question after that is, will they buy into a $2000 body and $1000 lens combination for an interchangeable lens system at enough volume to be profitable?
Canon and Nikon have an advantage selling their new lower-end FF SLR bodies: they already have a lens line that works with them. Even though that is still an ongoing work in progress as they continue to revise and optimize for the digital sensor, it's huge leg up on the introduction of a new, compact, TTL electronic system of similar specification.
I think it will happen, and it's quite possible Sony will have to be the one to do it. Leica's agenda is higher end than the mass market product that the mirrorless call wants, and they don't have the resources (or motivation). Nikon and Canon are concentrating on their traditional SLR base for the present. Ricoh/Pentax are probably better off continuing with their Pentax SLR and GXR system efforts, given that they are both relatively niche market brands at this point in time. Olympus and Panasonic are wedded to the FourThirds format for the present, and are already doing well there. There really isn't anyone else out there with the resources to tackle this kind of thing.
The future will tell the story.