Originally posted by normhead The only thing I want out of a Pentax FF, small size, and SR. I don't buy that SR has to make it bigger than a K-3. The sensor will be 36mm by 24mm.. how does that put the SR system as larger than 70mm?
In addition to what Fogel70 wrote the mirror, mirrorbox and shutter must be larger. It is possible the mirror motors must be larger to drive the heavier mirror. All that extra mass must be damped somehow to control vibration. All that larger stuff still has to fit around the (new, larger on the K-3) screwdrive motor. Any additional heat must be dissipated somewhere. It is likely the focusing array will be different to cover a larger area - DK if that would mean larger. If it has Wi-Fi the antenna has to be outside the metal frame (assuming they stick to a premium body) and any hinged LCD (645Z-style) might need room. Anything they move has to go somewhere, and move something else. You can go on and on with this line - I assume Pentax engineers have done for years, off and on.
One consideration might be whether the market would accept a smaller IBIS assembly in a smaller camera and a
slight crop of the FF sensor to allow for sensor shift. If that was the compromise, would you accept it?.
IMHO the likelihood any coming
Premium Pentax FF is the same size as a K-3 is very slim. A less robust, or intentionally simple FF (the Unicorn digital K1000) maybe could work.