See the review of the Pentax 645D in Medium Format.
David P writes:
I concur with your wish to see a fixed lens 56x56mm MF digital camera though it seems unlikely to happen, if only because demand would probably be low. However it set me thinking about the 18 months during which I owned a Pentax 645D system.
I sold the Pentax and its lenses - for reasons too tedious to go into - in favour of a Nikon D800 (I was already a very long time Nikon user). What struck me immediately and forcibly on using the 36mp D800 was how greatly inferior it was in IQ terms to the 40mp 645D. I had expected a slight difference in IQ but the Nikon was simply not on the same planet as the Pentax. Not only that, but the Pentax flattered the user - it was EASY to shoot images with superb IQ, whereas the Nikon was extremely difficult to get the best out of. That is, it wasn't hard to get pleasing images out of the D800, but very difficult to get image-files which were significantly better than those from the 12mp D700, my other FF camera-body.
It seemed as if the old divide in quality between 35mm (FX) and MF cameras still existed in exactly the same manner and degree (as in the days of film), in spite of pixel-count etc. Except at high ISOs, the Pentax trumped the Nikon in every way, in spite of the Nikon's sensor being a couple of generations later and presumably more sophisticated.
I wonder if this difference is something you have noted, and what you think the most likely reasons are for its existence.
Congratulations on the continuing high quality of your site; one of only two "must-view" sites on the entire internet, imho.
DIGLLOYD: The Pentax 645D does not have an anti-aliasing filter on its 40-megapixel 4:3 CCD, so the appropriate comparison is with the D800E, though the D800 model is the same except for necessary sharpening differences.
The 40-megapixel CCD sensor in the 645D is terrific, no doubt there. And admittedly a CCD image has a certain appeal over CMOS from what I can see, the Leica M9 vs M240 being the most notable case. It’s a real difference in style and I can see that some shooters would really respond to it (I did).
There is also a style difference that results from the format: the longer focal length. And also the aspect ratio. But with a 44 X 33mm sensor, this difference is not pronounced.
And I have to offer a caveat: I never did have a chance to shoot the D800E and the Pentax 645D at the same time; I had the Nikon D3x at the time.
“very difficult to get image-files which were significantly better than those from the 12mp D700, my other FF camera-body” means to me that something in the equation was an issue (lenses, technique, focus errors, post processing, etc).
But I have a hard time agreeing with the “not on the same planet” statement. The D800 has a wider dynamic range and better color accuracy and with top glass and sharpening produces 1st class images. Most of the Pentax lenses were disappointing, not even in the same league as Leica S glass, and lacking the sparkle I enjoy from my Zeiss glass.
David P responds:
"Not on the same planet" was an exaggeration and therefore unfair to the D800
I'll stick to my guns, however, in saying it can be a difficult camera to get the best out of; but having recently purchased the Zeiss 21 and the Sigma 35/1.4 I do see what a difference top-quality glass can make.
My Nikon lenses were probably not all of the first rank. And when still unsure of the D800's capabilities, I did eventually do some careful side-by-side tests with the D700 which showed that the D800 had better colour, contrast and detail. In the real world I still sometimes find those improvements to be elusive.
DIGLLOYD: Top glass is essential with the D800. To see what it can really do, the Zeiss 135mm f/2 APO-Sonnar is instructive. The Sigma 35/1.4 is a good choice as is the Zeiss 21/2.8 Distagon, though in truth most all wide angles of any brand really need improvement to fully exploit the D800/D800E. But the Pentax 645D has similar limitations.