Image from Pentax UK.
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. Suddenly, f2.8 maximum apertures don’t seem to matter quite so much anymore. Handholding and insufficient shutter speeds don’t seem to be quite such critical limitations.
The rest of the spec sheet suggests the 645Z isn’t a D4S replacement, but then again, consider this: if at the pixel level it loses a stop or two in noise to the D4S, but has nearly four times the pixel count – downsampling is going to yield an amazingly clean image, regardless of the ISO used, with that medium format look*. And that makes things interesting.
*Related to the depth of field properties of the actual focal length of the lenses, and irrespective of the field of view. Smaller formats mean shorter focal lengths for the same equivalent FOV, and the attendant depth of field properties that go with it – i.e. a lot.
However, unlike the Hasselblad and Phase, I don’t think the 645Z requires such an enormous shift in the way you work, or familiarity with older cameras: a lot of hardware and UI elements appear to be ported directly over from a K-3, right down to focus peaking, a 27 point AF system (with 25 cross type points) and the button assignments. It’ll do 3fps and 1080p30 video (that should look interesting). There’s a solid AF lens system available already, and prices don’t seem to be unreasonable – older MF lenses are legion, and they’re even cheaper (I’ve seen excellent lenses as low as $75!) Once you get over the size and physical aspect of things, it doesn’t seem at all intimidating. It’s even built like a current pro DSLR too – all magnesium alloy and fully weather sealed. What it will do, and quite impressively, is extend the conditions under which the next step up in image quality from a DSLR can be obtained – consistently.
I do have two concerns – perhaps that’s too strong a word – however. The first is that we may not really get as much of that ‘medium format look’ as we think: I have always strongly suspected a good part of it is down to the native tonal response of the sensor, and we all know that the linearity of CMOS sensors might be great for extended dynamic range and noise control, but it does mean that color and tonality aren’t quite as good as CCDs. Hasselblad and Phase have made it clear that the sensor and associated hardware is capable of native 16 bit output, and they’re offering 16 bit files; however, it isn’t clear that this is the case with the 645Z; in the past .PEF files have been 14 bit, and DNGs just 12. Hopefully this situation changes and we get the full 16 bits. It would be a shame to compromise twice. In any case, I don’t imagine the tonal latitude will be any less than the D800E, which is also limited to 14 bits; I figure if we can work with that, anything better is a bonus.
Secondly, there’s the lenses. Pentax USA has committed to introducing an additional 13 lenses (from their current overseas lineup) into what I suppose they want to become their largest market; they should be commended for this. However, I wonder how many of these lenses are up to the task of resolving as expected on a sensor of that pixel density and size; as we saw with the introduction of the D800E, a lot of lenses aren’t anywhere near as good as we thought they were initially. I suspect that the newer lenses designed post-645D will be fine – such as the 25/4 – but some of the older glass may prove disappointing. Personally, what I find interesting is that there is a) a Hasselblad/Zeiss V to P645 adaptor, and b) a lot of the lenses I already have have been tested to be excellent performers on the 645D, even wide open. It may well prove to be an interesting digital back – I’m not particularly worried about manual focus limitations, because we now have both live view and focus peaking, and this is the kind of camera that goes on a tripod anyway – it seems silly to buy one with the intention of seeking out optimum image quality and then leaving some of it on the table.
Possible shortcomings and limitations aside, this camera is really a slap in the face to everybody else: it’s basically made Nikon and Canon offerings above the D4 and 1Dx pointless, because they will a) be priced pretty close; b) have smaller pixel pitches and hit diffraction faster, and have limited usable lens selections; c) not be much smaller. You could get three of these and a lens or two for the price of one H5D-50C, or four for an IQ250; if Leica uses this sensor in the next S, you can bet that the price point isn’t going to be less than the other two. What Pentax has done is out-Nikon’ed Nikon; they’ve copied the D800E’s price-performance ratio and turned it up another notch.
I’m personally looking forward to reviewing this one as soon as a demo is available. If anybody happens to know some folks at Pentax, I’d love to get in touch. Mainstream medium format, I bid you a warm welcome. 16×20″ Ultraprints, anybody? MT
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Filed under: Gearhead: Reviews
