I read with interest the review of the P25 back vs Ids MkII. Now, allow me to be a bit controversial and provocative here and then you can let me have it ...
I'm assuming here that in comparing apples and oranges, Michael is doing this from the perspective of a pro landscape photographer looking for the best tool. I can't imagine who else might be trying to make a decision between these two very different machines. Yes, I suppose that spending $30,000 on a back gets you better image quality than an $8,000 camera. Not very relevant to the 99.9% of folks who will never have to make this weighty decision. But interesting nonetheless.
Let's leave aside the obvious advantages of digital for a moment. Digital has many advantages but two of them are not resolution or dynamic range. Michael says that dynamic range is linked to noise. Sure it is. But I like to think more about how dynamic range is linked to resolution. The lower the resolving power of the chip, the less able to reproduce detail and the greater the tendency to lose detail in shadows and blow out highlights. This is where all digital cameras lose out (still) to MF film.
IMHO (and in that of many other photographers), a 22 MP back still does NOT have the resolution or dynamic range that one can still get from medium format film. From a cost/performance perspective, a $35,000 investment in a digital back, MF camera body and a good selection of lenses make no sense whatsoever unless you are a pro studio that requires a smooth, fast and efficient workflow and time is money. For the landscape photographer, it's a big stretch to see how this investment could be justifed no matter how many galleries your work appears in. A MF film camera will give you richer tonality, more resolution and require less time in photoshop. Not to mention at a fraction of the cost (assuming you do most of your work IN the camera, and not in photoshop).
Also, scanner cost/performance is improving so quickly that it makes more and more sense, FOR THOSE WHO NEED TO MAKE LARGE PRINTS WITH HIGH RESOLUTION, to keep their medium format cameras and scan the film in a good scanner. The newly introduced EPSON GTX-800 flatbed scanner is a good example. ( Most of you haven't seen this scanner yet- it just appeared in Japan) This scanner has a dMax of 4.0 at a cost of about $600. Even a $2,000 Coolscan 9000 (dMax 4.
is still more cost effective. You will end up with more resolution, broader tonal range at a lower total cost per picture. And perhaps even save time too.
BTW, I own a measly Canon 20D and love it. I am seriously going to be looking at the Mamiya ZD MF camera too. But for now, for landscapes, I believe that digital is still inferior to film in these respects.