Ray,
While I could have much to tell you, for the moment I won't comment further on this post, except to make one point and to ask you a question. The point is that I'm not a wealthy person who can afford to spend this kind of money frivolously and I wasn't either an idiot or on drugs when I bought that system. The question is: have you personally had a recent opportunity to compare similar images, having high scene DR, as rendered by a high-end DSLR and a Phase-1 P40+ or P65+ back?
Mark
Mark,
That's a fair question and I'll attempt to give a fair answer. There are many, many different models of cameras on the market. It would be unreasonable to expect anyone to hire each model of camera with lenses and compare performance with what they already own (or hire two camera models at a time) before making a purchasing decision.
Fortunately, we have a number of organisations which specialise in performing such tests and which make the results freely available on the internet.
I'm very well aware that larger sensors collect more light, and as a result of that fact are able to produce subtle improvements in image quality which can be clearly seen when such images (or prints) are viewed from a close distance.
For the past 5 years or so, I have owned mainly two different formats of cameras which differ in size by a degree which is just as great (approximately) as the difference in sensor area between a P65+ and a full frame 35mm. (ie. various Canon cropped format cameras plus a 5D, the 5D sensor being 2.6x the area of the Canon cropped format DSLR).
I'm no stranger to the advantages of the larger sensor. Generally the larger sensor provides higher resolution, smoother tonality, greater color sensitivity, lower noise and shallower DoF at the same f stop. These are all good reasons to buy a large-sensor camera (with the possible exception of shallow DoF).
They are the reasons why I am hesitating in choosing between a 7D and a 5D2 for my next upgrade. The 7D has the clear advantages of longer reach, lower weight, faster frame rate, possibly better autofocussing, and the 5D2 has the other advantages mentioned above.
It's interesting that the DR of the 7D appears to be just as good as the DR of the 5D2, up to ISO 400. Beyond ISO 400 both the old 5D and the new 5D2 outshine the 7D, but not by a huge amount. At most by a full stop or slightly less. Nothing like the magnitude of the DR differences between 35mm and MFDB that Mark Dubovoy claims.
Another important point which is so often overlooked when comparing image/print quality is viewing distance.
Anyone who views a print from a closer distance than 1.5x its diagonal could be considered a pixel peeper. No harm in that . But I really question the wisdom of spending huge amounts of money on equipment which produces superior image quality which is discernible only from a pixel-peeping distance, or a closer distance than is required to appreciate the composition as a whole.