Due to recent unfortunate events (self inflicted ), I'm now in the market for a new back for my Alpa Max plus, potentially, as a replacement for my D3x if I transition to using my Phase DF as my principal landscape DSLR. Budget for new retail is up to the Aptus II-8 ($15k), or if someone can give me a REALLY good reason why, potentially stretch (with some discomfort) to the Phase One P40+, perhaps bigger & better if I can find a refurb or private deal. Above that and it's into competing with a replacement Range Rover Sport ... and the camera loses at that point. The miserly part of me wants to keep costs reasonable as this is my expensive therapeutic pastime and not a business expense.
My question is what recommendations do folks have regarding #pixels vs sensor coverage primarily for use on a technical camera?
My Aptus 65 was 44x33mm and I know that I can obviously move to 40mp at that size via the Aptus II-8 or P40+. (or of course I could just get a Aptus II-6 as a replacement). However, the Aptus II-7 (or 75s etc) have larger coverage in terms of 48x36mm for a slight increase in resolution - I haven't done the math but I suspect merely due to extra real estate at the same pixel size.
The trade off as I see it with the larger sensor is that I would have a slightly larger image area to compose against on the ground glass with mask, which I would find useful but not compelling, vs higher pixel density at the same imager size. The smaller sensor size does have some advantages in terms of shift/rise coverage and lens sweet spot due to the crop. With the Technical camera I don't feel limited in any way as far as wide coverage is concerned as I'm not typically a super-wide shooter and actually stitching handles this for me.
What I haven't been able to ascertain is whether the 7.2 micron pixels of the II-7 (or II-6) would be beneficial vs the 6 micron pixels of the II-8/P40+ that provide the resolution boost. In an ideal world I would assume yes, at least based on my previous Nikon DSLR experience where big fat juicy pixels = more sensitivity/cleaner higher ISO support. However, I haven't seen anything to suggest the same is true with the MFDB's.
With respect to using the back with the DF body and lenses, there would be some advantage with a larger sensor coverage in so far as I'd get less of a crop factor on the Mamiya/Phase glass - the one area where giving up the Nikon full frame for wides is a concern.
Btw, I never did find any closure in the previous threads about the advantages of the P40+ vs Aptus II-8. I assume Sensor+ pixel binning for higher ISO support would be one (not really relevant for my proposed use) but were there others?
Thoughts & Fall 2010 perspective on this? Any field experience input would be very welcome in helping me decide (along with obviously my dealer discussions too).
Thanks in advance.