Originally posted by troika How small and how cheap could it be?
It would be about the size of a K-1... if you are willing to sacrifice the screen (and thus, one of the major advantages of digital photography), you can shave off 7mm from the depth... lets be generous and call it a centimetre. So you can save a centimetre of depth and maybe a few millimetres of height. You might save a bit more if you massively compromise on build quality.
Cost wise, about the same as a K-1... maybe $200-$300 (if you sacrifice the screen), assuming that Ricoh expects similar sales volumes (allowing for a similar apportionment of development and capital costs).
The reason is the same for both - the sensor. Ignoring the capital, manpower and logistics costs (which would be substantial) and just looking at the component costs of the camera, the sensor comes way, way out on top. There is a pile of electronics that drives that sensor, and that's expensive too. Much of the other hardware existed back in the days of film (from metering to AF, and non-electronic parts like the shutter, mirror, prism, etc). The 'new' stuff that isn't essential for a digital camera to actually record in image is stuff like the GPS, screen and IBIS - component cost for this stuff isn't insubstantial, but it also wouldn't add up to much. Most of the other fancy features are software - it costs essentially nothing to include the software, the R&D having already been spent, and thus needs to be recovered for Ricoh to turn a profit, regardless of if it is included. Other makers like to impose artificial software limits on lower-end cameras as a means to push consumers to more expensive models... with the latest Pentax cameras including flagship features such as pixelshift this obviously isn't Ricoh's style.
Size wise, again, sensor. Big sensor needs housing. All the fancy electronics that drives it (and there is a lot...) needs housing. Camera sensors sucks power, lots of power, the bigger the sensor, the more it consumes - so you need a big battery. All those electronics also need power, so even more battery. Camera sensors also produce lots of heat (and big sensors produce more heat... see the theme with big sensors?) - heat dissipation is a real problem in cameras with large sensors, look at the cut away of the K-1, that big air gap behind the sensor is to vent heat. Heat is the enemy of electronics - for a start heat build up will introduce more noise into your photos, and if it gets really bad it'll kill things (or at least shorten lifespans). Unlike mirrorless we are stuck with a pretty deep mirror box and legacy flange distance, so Pentax cameras can't take space from the front and add to the back (to help with heat). This isn't a problem unique to Pentax, see the sizes of the FF DSLRs from Canon/Nikon/Sony.
By FF DSLR standards the K-1 is already pretty compact. Engineering wise there probably isn't much more room to move (and if there was, I suspect Ricoh would have taken it - making DSLRs compact is something Pentax is known for).
So Ricoh could produce a feature-stripped down version of the K-1, retailing for slightly less in a slightly smaller package, while increasing the strain on their production and supply chains. Or they could view the K-1 as already meeting your needs, after all, you don't have to use the GPS, AF or even the meter. From a business perspective I can see why they have taken the route the have.
Originally posted by troika And how soon could I pre-order one?
If you want to see how a retro-FF-DSLR would work, look no further than the Nikon DF - and while I like the idea of the DF (and so did many others), it turned out that nostalgia didn't translate into sales.
So the answer is probably never, or maybe not in the foreseeable future. If we can get to the point that we are able to miniaturize the sensor, all the associated electronics, the power source and any heat dissipation into something the size of a roll of 135 film and a pick up spool (and theoretically we will get there eventually, electronics keep shrinking) then maybe. But even then I am not sure if there is business sense in creating something that tries to emulate a SLR body that can be easily had for under $100 and a roll of film.