A couple of days ago, Pentax threw down the gauntlet to the other medium format digital camera makers in the form of the 645Z. It uses the same ~50MP 44x33mm CMOS as the Hasselblad H5D-50C and Phase One IQ250, but with one critical difference: unlike the Hasselblad and Phase One, it’s feasibly within the reach of a whole load more people. And it isn’t just the shocking price – $8,500 plays$29,000 (Hasselblad) or \$37,000 (Phase) – it’s the UI and operating gestalt, too. I think what we’ve just seen is an early game changer.
Pentax released the 645D some time ago to not that much fanfare, but a rather interesting price – especially compared to other medium format options of the time. The 645Z is now a direct comparison to the Hasselblad and Phase because of the choice of sensor; it seems that only Sony is alone in offering a medium format sensor with current photosite technology. My guess would be that it shares a lot at the architecture level with the D800E’s sensor, which is no bad thing. I believe the MF sensor’s pixel pitch is slightly larger, though. It’s also the reason we see an enormous jump in shooting envelope and usability: we go from ISO 400 being the absolute maximum (with significant NR work afterwards in post processing) to ISO 6400 being the highest rated sensitivity, and HI1 to HI4 options all the way to 204k thereafter. That’s four stops
via MF digital goes mainstream: early thoughts on the Pentax 645Z – Ming Thein | Photographer.
Sensor dimensions are 43.8 x 32.8mm, and as shown above right, that's quite a bit bigger than a 35mm full-frame sensor. It's a Sony CMOS chip, which is in itself big news.
Pentax 645D and 645Z shooters now have a total of 17 lenses (12 primes and five zooms) to choose from, plus three more zooms still on the roadmap. Everything from 33mm to 300mm is covered without gaps by the zoom offerings, while the primes range from 25mm to 400mm.
via Pentax 645Z Review: Preview.