Originally posted by Lowell Goudge yes they can strike a hole in the market, just like they did with the LX and toss a ton of money into it.
Since even the big boys are 18 months since their last FF and considering soney is not making the sensors any more, that should tell you something.
And this is the problem. The only sensor available is likely the Sony A900 version which is a dated design with poor high-ISO stats dating from 2008. It is unsure if Sony will continue FF development. What Sony is up to is anyone's guess. They struggle to get traction in the market despite some interesting engineering. I suspect we will see a Sony pellicle FF with extensive video features in a new body with a new sensor. This is the same supply for Pentax if there were an FF option.
Pentax's SR is also an issue. It takes up considerable space in the body. You'd be looking at a camera A850/900 in size. This is a reason why Canikon left SR in the lenses, and even then not all their main lenses for FF have that capability due to size constraints. anyone thinking that a Pentax FF will be the size of a K-5 is in la-la land.
Instead, Pentax went with the 645D, which is probably not much larger than a Pentax SR-capable FF DSLR would be. You're still looking at lugging a big body and big glass around. In some ways, a better solution for Pentax FF fans is to advocate a lower price point for the 645D. If they could get a 645D kit system down to US$6,500 they might make a splash. A lot of prosumer energy and discretionary $ went in MF up to a decade ago, and it can happen again (I have a film Mamiya kit).
Realistically, if you make an FF DSLR camera, you need to follow the path of Nikon. A lower-end model, high-ISO wunderbeast like the D700, and a resolution beast like the D3. Couple that with about 20 lenses including stellar zooms from 14-400mm. Not having this duality is partly what stalled Sony's system. The D700 is going to go down as one of the most influential camera designs ever and is incredibly hard to compete against. It's a big reason *for* switching brands. Topping the size/performance/price/lens availabilty of that camera is difficult for a company reliant on external sensor supply.
FF will come when APS-C has reached its design limits and better IQ and performance can only come from larger sensors. To future-proof itself from this eventuality, Sony designed the NEX for FF. Mirrorless and FF will eventually converge, at which point you may see Pentax looking at this again. The major issue is the cost of sensors and their supply. The market is at least 5 years away from that.