Ray - a simple question to help evaluate what you are saying: how many MF systems have you personally tested at varying ISO settings, printed the outcomes and seen the results?
I contest the notion that these systems can only be advantageous under controlled studio conditions. It's just not true.
Only two, Mark. They were the Mamiya RB67 and the Fujifilm GW690III. I believe the increased resolution from these two cameras would have
exceeded the resolution of my Canon 35mm film-camera by a
greater degree than a P65+ exceeds the resolution of a 1Ds3, 5D2, A900 or D3X.
I bought these MF systems second-hand for what I thought was a good price. I got the impression that many professional photographers at the time, around the year 2001, were dumping their MF gear in favour of lower resolution digital which was far more convenient to use and the images far cheaper and easier to process.
Around this time, Canon's first DSLR offering, the 3mp D30, was selling in Australia for around A$6,500. I preferred to spend A$6,000 on Nikon's first affordable MF scanner, the 8000ED, so I could scan my 6x7cm and 6x9cm negatives which would provide considerably more resolution than a 3mp DSLR.
If I'd known at the time that within 3 years or so Canon would double the MP count and produce a D60 at a lower price than the D30 (I recall the 4mp 1D preceded it), I would not have bought into those MF systems.
As soon as I experienced that amazing convenience and flexibility of the D60, all my film gear including the higher resolution MF gear, remained on the shelf.
I'm a bit fanatical in some respects, but not so fanatical that I'm going to lug around a lot of heavy and inflexible gear for the odd occasion that I can get a high resolution shot that wouldn't be possible with a DSLR because the scene didn't lend itself to a stitching procedure.
I wonder if you realize, Mark, that half a dozen D7000 images (perhaps fewer depending on overlap) stitched to produce the same file size as a single shot from a P65+, would actually have equal or higher image quality in every respect.
The D7000 would have marginally better color sensitivity, but so marginally better we can call it equal.
The P65+ would have
very marginally better tonal range, but so marginally better we can definitely call it equal.
The P65+ would also have marginally better SNR at 18% grey, of the order of 1.2dB. Definitely of no consequence.
However, the stitched D7000 shot would have almost 2 stops better DR.
Now that's definitely of consequence, wouldn't you agree?
One should also bear in mind that all these improvements (or equalities) of the stitched D7000 image are achieved at approximately one stop higher ISO; to be precise ISO 83 for the D7000 as opposed to ISO 44 for the P65+.
It is assumed if one is stitching images from a smaller format to reach the same file size, FoV and DoF as a larger format, then one would use the same focal length of lens at the same F/stop as one would use on the larger format for the single shot of the same scene.
There might be further nitpicking issues regarding AA filters, but I think these would be offset by the fact that lenses designed for 35mm format, with their smaller image circle, usually manage a slightly higher MTF response at any given resolution than equivalent quality MF lenses. If it's not completely offset, then stitch 8 images instead of 6. No big deal.
I think the stitched image would also have the advantage of better edge performance. As you know, all lenses have a significantly worse MTF response towards the edges, including MF lenses. A 35mm lens on a D7000 not only has the advantage of the soft edges being cropped by the sensor, but the edges of the stitched composition will have the benefit of the sort of resolution one would expect from the central area of the image circle.
MFDB just doesn't make sense to me. I understand very well the principle of the 'best tool for the job'. If I were in the position of certain professional photographers who always know the nature of their assignment beforehand, then I would be in a position to choose what I thought was the best tool for a specific job, and there might well be certain occasions when I would select the MFDB system from the shelf, if I had an MFDB system.
However, that's not my situation. Photography for me is an adventure. I may have an idea of the sorts of scenes I will encounter, but for me, flexibility (consistent with good technical quality) is the name of the game.