Originally posted by spqr 14 bit is over 4 trillion colors, I don't think that is going to pose a problem if it is getting that full range. I doubt any human eye would be able to distinguish the difference. And, as others have noted, is the additional 2 bits that the Mamiya is getting worth twice the price? Again, I doubt it.
However, Pentax hasn't been terribly active in medium format for a while, so they have some ground to catch up. There's an investment in systems from Mamiya, Phase One, etc. that are not going to be tossed away just because Pentax has a digital version of the 645 now.
As for me, I'd love it, but that's going to be way out of my price range as an amateur unless I get very lucky in the lottery.
Your point is almost valid, here we are speaking about 14bits per channel. In Raw, evey sensor dot have a color, the pattern being organized in a bayer matrix, to display the image every pixel will be interpolated from the dots and its neightboors. That's the reason why Raw readers will have different rendering on default settings.
When I say above that printers have only 8 bits color depth, it doesn't mean that it can render only 256 colors of course, but that each Red, Green and Blue colors are coded on 8 bits, i.e : 256x256x256 = 16 Million nuances
But in fact, the human eye is able to make the distinction of much more tints, that's why on a computer generated image (understand "no noise") a trained eye will be able to make the distinction between 2 tints levels.
Now back to camera, having a channel coded on more bits does have some utility:
1. Printer will progress, eventually outperforming this 8bits limit
2. This helps to have a better interpollation in the rendering engine
3. When modyfying an image, this margin allow a lot more room for ajustments, for example +1EV expostion more or less means that you multiply the value by 2, wich means that you need 1 more bit of precision.
So 14 bits vs 16 bits are indeed a disavantage in theory, but in practice, you have to the images on prints to make any comment. Even professional screens are not able to render anything close to such a color depth.