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Pentax 645z – In-Depth Review

By Michael Reichmann

Let's start with the stipulation that this won't be a formal review. It won't be a first look, and it won't be a field report. Rather, this is a report about my daily use of the 645z, which I purchased in early August, 2014 and the things that I have discovered while working with it.

In July Ricoh / Pentax Canada provided Nick Devlin and me with a pre-production 645z for a few days so that we could run some tests and write a preliminary review. As these things go, we did a pretty fair job. But I was left dissatisfied with what we had done, mainly because the 645z is such a rich instrument in terms of features and capability. It deserved more.

Let me note that in our review I wrote ..."just a couple of years ago the 645Z would have generated 'want bumps', but now, hardly at all." I actually now regret writing that facile comment, because on reflection, once the review sample 645z had been shipped back to Pentax I realized that in fact the camera pressed a lot of the right buttons for me (no pun intended – though the 645z does indeed have a lot of the right buttons to press).

This report then is the result of some weeks of almost daily use of my 645z and six lenses during August and into early September, 2014. I bought the camera from a Canadian retailer for my own long-terms use.

Please note that I will not be repeating technical tests done during that first review, so please have a look at it for the complete picture.

Railway Crossing
Pentax 645z with 45-84mm f/4.5 @ ISO 800

Medium Format – Has it Peaked?

I believe that so-called medium format is at a crossroads. Prior to roughly the year 2000 and the emergence of "affordable" DSLRs, medium format was just that – a film format that fit between 35mm and 4X5 sheet film; large format as it was then called. 35mm was convenient and inexpensive. Large format considerably less convenient and more expensive. Medium format was for those for whom 35mm was insufficient in terms of image quality for large prints or strong cropping, and large format which was cumbersome and expensive to shoot. (4X5" or larger sheet film was pricy to buy and pricy to process (especially transparency film)).

A large number of companies, Hasselblad, Mamiya, Rollei, Fuji, Bronica, Contax, Pentax, and a slew of speciality brands provided solutions at a range of price points. Medium format system cameras were priced at a considerable premium to 35mm, but their purchasers, who tended to be pros and wealthy amateurs, embraced the higher image quality that was offered, reserving large format and its astonishing image quality potential for those with specific shooting needs. Cameras also came in a range of sizes and configurations...all-in-one, removable backs, fixed lens, etc. More on this shortly.

Today things have changed, but in some ways not as much as one would think. Today's leading medium format brands are Phase One / Leaf, Hasselblad, Leica and Pentax. Mamiya is still an available brand, but it is now controlled by Phase One, and its cameras also appear under that brand.

(Rollei is still a player with the Hy6, though almost non-existent in most markets). 

For all of the doom and gloom that some web denizens preach, my sources tell me that at least one of the leading MF company's sales continiously exceed forecasts, month over month. And, certainly the new Pentax 645z seems to have created quite a buzz and strong demand in its niche. So, to paraphrase Mark Twain, the rumours of medium format's demise seem to be somewhat exaggerated.

The Format of Medium Format

Medium format used to mean 120 or 220 roll film and a range of image sizes from 645, to 6X6, to 6X9, to 6X7, 617 and more. Today medium format means everything from sensor sizes of 33x44mm for the Phase One offerings like the IQ250 / IQ140), 30x45mm(Leica) and 40X54mm (IQ180 / 280 / Aptus II 12/12R). The Pentax 645z is 32.8 mm x 43.8mm.

Resolution ranges from 40 Megapixels to 80 Megapixels. Some cameras use CCD sensors, while a newer generation uses CMOS sensors.

Some cameras are all-in-one, like the Leica S and Pentax 645z, while others like Hasselblad and Phase One are modular with interchangeable backs. All-in-one designs have the advantage of working like 35mm cameras on steroids, while modular cameras with interchangeable backs offer the advantage of their removable backs being able to be used on technical view cameras such as those from Alpa, Cambo et al. There are no fixed-lens medium format digital camera yet, but as this is being written Photokina 2014 is just around the corner.

Birds and Bales
Pentax 645z with 300mm f/5.6 @ ISO 1000

4:3 vs. 3:2

One aspect of most digital medium format cameras and backs worth noting, including the Pentax 645z, is that the native image aspect ratio is 4:3 rather than the wider 3:2 aspect ratio of both APS-C and so-called Full Frame 35mm. I have always found 3:2 to be either too wide, or not wide enough. This is, of course, a matter of personal taste, but I find myself cropping most 35mm images to something closer to 4:3, or even square.  

I am not a respecter of inherent camera formats. I crop to what an image wants to be, not what a manufacturer has arbitrarily dictated with the camera's construction. For me then, 645 is a much more pleasing format to be begin with and requires throwing away a lot less data to get an image shape that I usually prefer. This gives an even greater IQ advantage to 645 over 35mm in my hands.


Lenses

OK...here's the deal. There's good news and there's bad news when it comes to lenses. Pentax has been making 645 lenses for many years. There are some that are great, and some not so great, though few if any are really poor. Doing a bit of research on the Net, and browsing the forums and review sites will tell you what's what. Because there have been so many lenses over so many years there are also different models, some with AF, some not. Do some research and learn how to decipher the lens codes so you know what you're doing. (Hint – FA means autofocus).

With the launch of the 645z and the acquisition of Pentax by Ricoh, some new lenses have been released and quite a few older models which disappeared from US dealers shelves some years ago have been re-released. If you look on B&H you'll see that there's a good selection, but the new lenses and some of the re-releases are quite expensive. At least one of the new Pentax 645 lenses has built-in optical stabilization.

The answer to finding high quality lenses at good prices is eBay. There are many used lenses available from retailers in Japan. Because Pentax 645 systems have been very popular in Japan for years there is a healthy stock of used lenses, many in "Mint" and "EX++" condition. My experience is that highly-ranked Japanese sellers on Ebay are scrupulously honest and accurate in their listings and descriptions. Lenses will arrive by express mail in about a week to ten days, with on-line tracking, and most resellers offer 14 days refunds, excluding shipping.

The rub is that as the 645z gains in popularity (and this article will likely play a role), the stock of high quality used Pentax 645 lenses of recent vintage (meaning FA, with autofocus) will decline, and prospective camera buyers will end up paying either higher used prices, or the premium prices of the re-releases, which can be 4X more than high quality lightly used versions.

While waiting for my 645z to arrive at my dealer, I spent several days reading reviews, speaking with other Pentax 645 users, shopping online, and comparing prices. In the end I bought six lenses online, all from Japan-based dealers on eBay. 

NEW

PENTAX FA 645 35 mm f/ 3.5 AL

Pentax FA 645 300mm F5.6 ED 

USED (Mint or A++)

Pentax SMC FA 645 75mm F2.8 

Pentax SMC FA 645 MACRO 120mm F4

Pentax SMC FA 645 Zoom 45-85mm F/4.5 

Pentax SMC FA 645 80-160 mm F/4.5

These six lenses came to about $6,500 combined. Not much more than a single lens from some bigger brands, or even some of the new lenses from Pentax themselves. 

The Pentax 645Z Can Be Purchased at BH Photo

Of course the question becomes, can these lenses keep up with the demands of this camera's new 51MP sensor, arguable the best sensor ever in a digital camera? The answer is mixed; yes and no. Frankly, I believe that the best medium format lenses are Leica's, for the S series cameras. The new generation of Schneiders for the Phase One system are close to the Leicas, or equal. One tier down from these are Hasselblad H series and Pentax 645 lenses. Neither are the ultimate, and may leave a bit on the table when it comes to bench testing and MTF charts. But, in the real world, and making prints in the 24X36" range, one would have to do some serious pixel-peeping to see the differences.

And that then lies at the core on my decision to spend the next couple of years working with the Pentax 645z. I have a range of needs, from street shooting and documentary work, to landscape and nature, to portraits. I therefore need a range of lenses. At about $15,000 for the camera plus six lenses, I believe that I've put together a highly versatile and extremely high quality system that is a nit-picking smidge away from being as-good-as-it gets. A Leica S with a full set of lenses would cost 3-4X what the Pentax does, and only give me a modest improvement in IQ. It wouldn't though give me the high ISO capability of the Pentax, and many of the features which I discuss further on in this article, and which I find to be of great value for my work.

A Hasselblad or Phase One system would offer other advantages, and those who have been long-time readers know that I have owned both systems and think highly of them. But, my "job" and my "pleasure" is to stay on top of the state-of-the-art, and right now (Q3, 2014) when it comes to medium format camera bodies, the Pentax 645z is it. Next year...who knows?

There are also other choices besides Pentax 645 lenses. Inexpensive adaptors are available for Hasselblad V series lenses, as well as for Pentax 67. You won't have AF, and aperture will be manual on the V lenses, but there are some screaming bargains to be had. For the slow-working landscape photographer these may be just what's needed to keep you working once your Visa card has been drained by the purchase of the 645z body.

One final comment on lenses. Other than for a couple of older lenses, there are none with leaf shutters. For pros working with strobes this can be an issue, but shouldn't concern anyone else.

Hidden Barn
Pentax 645z with 75mm f/2.8 @ ISO 800 

The Body and Its Features

For some photographers, not to mention apparently a number of popular web reviewers, image quality is their primary interest, be it due to the sensor and / or lenses. While I share a strong desire for utmost image quality it is never at the expensive of handling and features. 

Of course I do what all photographers do with new gear... I do test shots, looking at noise, resolution, lens aberrations and the like. But once the pixel peeping gets boring it's the way that a camera performs in the real world of shooting in the field that gets me excited. In other words, how well (or how poorly) a camera and its lenses perform as a system is what sets my juices to flowing. Pictures of walls and rocks and backyard miscellanea are useful in the courtship phase, but when it comes to a real relationship a few visual pimples are soon ignored compared to the system's overal performance. 

In other words, if camera system "A" gets a 10 for image quality and a 8 for usability, while camera system "B" gets an 8 for image quality but a 10 for usability, I'll choose system "B" every time. All other things being equal (such as price), for me usability trumps ultimate IQ. And when price plays a huge role, as it does with the Pentax 645z compared to its peers, this seriously affects the equation.

When it comes to shooting in the real world a camera system needs to be an extension of ones eye and brain. Like a musician playing their instrument – critical factors are – what to press, what to turn, and what these movements will accomplish to help capture an image as the light is fading or the scene is quickly evolving. Controls that get in your way, or important function selections that are buried deep in a menu system, can kill a camera's usability, and that means losing the shot. Lose too many shots, and I'll lose the system, quickly. It's happened....more than once over the years.

Seemingly, some camera makers design their products either by committee, or with little if any input by actual photographers. Cameras that are designed with a photographer's sensibility are immediately obvious, and Pentax as well as its new corporate owner Ricoh have always both been highly regarded as designers of some of the most photographer-centric cameras on the market. Simply put, the Pentax 645z raises that reputation to a new level.

It only takes a few minutes holding a 645z to realize that this is a serious picture taking machine. No one will buy this camera for bragging rights. If you see someone using a Pentax 645z in the field chances will be that this is a knowledgable, serious photographer who doesn't care what the cool kids are using these days, but rather is one who knows what they need for their type of photography.

In Hand

Cameras can be more than just devices for taking images. Much more. For some they are just tools. For others they are grown-up toys. But for many of us they are the tools that define our art and our craft and so go far beyond just being utilitarian devices.

It is for this reason that there are so many on-line punch-ups when it comes to cameras. Just as, back in the day, there were in North America Chevy fans, Hemi champions and Ford heads, today people derive some personal identification and identity via the cameras that they own and use. Even pros at a media or sport event find themselves grouping into Canon and Nikon camps. At football games one sees the white lenses and the black lenses, and rarely will the twain meet.

That's OK. Like monkey's with shiny beads we derive pleasure from our possessions, and that's nothing to disparage. Simply human nature. But, at a more mature level (and we are all mature here, aren't we?) people find themselves bonding with certain technological artifacts. Cameras are a prime example, so why pretend otherwise?

For instances, there is one major camera brand which I find myself hardly able to use with any satisfaction. The controls are highly modal – something I dislike, and the "feel" of the body is just not very appealing.  Another major brand has a user interface that appears straightforward, yet when I come back to it after just a few weeks away it appears opaque, and takes some time for refamiliarization.

But, turning to the Pentax 645z, there is something so straightforward and "honest" about its bulk and control interface that I almost break a smile every time I pick mine up. Yes, it's big, it's heavy and it's quite complicated beneath its basic interface. But, as I wrote in my initial impressions review, for me it presses all the right buttons, and in return I press its.

It is worth noting that the 645z body is weather sealed, and there are some videos around the net that show all kinds of abuse being heaped on the body. Most older lenses are not weather sealed, though a few newer ones are, and so a good rain cover is a worthwhile investment.

Abandoned Tractor
Pentax 645z with 80-160mm f/4.5 @ ISO 160
(intentionally desaturated and tinted

Aperture Rings

Call me old-fashioned, but when Nikon, Canon and others removed the aperture ring from lenses some years ago I believe that photographers lost something of value. All FA Pentax lenses have real honest-to-goodness aperture rings as well as a locking green-coloured "A" position. In A the lens works just like any auto-diaphragm lenses and the camera's control wheels can be used to set it. But when you want the tactility and visibility of an aperture ring, they are there, and I for one am glad that they are. I use the ring all the time when working in Aperture priority mode. I just like the way that it feels when I work this way.

Larger Sensor

Some people may quibble about 51MP not being that much larger than 36MP. Well, they're off the mark, because the combination of larger sensels and more sensor surface real estate does add up to an appreciable advantage over 36MP. This size sensor is about 1.7X larger than full frame, which is an even greater ratio increase over APS-C's 1.5X or 1.6X difference from full frame 35mm.

I have a 36MP Sony A7r and have also extensively used the Nikon D800e. I can state unequivacally, based on my experience, that the real-world difference in sensor size and resolution is palpable.

HI ISO

One of the things that got me thinking about this camera's potential advantages were the results in terms of image quality and high ISO performance that the new Sony 51 MP sensor produced. It struck me that with the ability to realistically and regularly shoot at up to ISO 12,800 with a medium format camera, and with quite low-to-manageable noise issues, it was a game changer, at least for some of the shooting that I do. I have always been loath to work hand-held with MF. Needing to shoot in the ISO 50-400 range to maintain decent quality, especially because most MF lenses are on the slow side, means it's use a tripod or go home. Certainly street shooting with MF is a challenge. Yet, for gallery sized prints, and the type of tight cropping that my style of shooting requires, bigger simply is better. 

What some weeks of use has shown me is that I can use the 645z in its TAV mode when hand held. This mode allows one to shoot with both a manually set shutter speed and aperture, with the camera setting the ISO as needed between user-set limits. Yes, some other cameras can do this, but on the Pentax this is a separate mode that can be engaged with the turn of a dial, while the camera remains in manual ISO in other exposure modes. Great photographer-centric thinking. 

Thus, for hand-held shooting, I am free to set the camera's shutter speed to what's needed (typically 1/focal length X2) so 1/125 sec for a 75mm lens, and the aperture to the DOF demands of the particular scene. With ISO 12,800 as my top Auto-ISO setting, in this mode I can do street shooting with any lens in almost any light. If the ISO hits 12,800 a bit of noise reduction is needed, but otherwise there's hardly any concern about noise, and dynamic range holds quite well up to about ISO 6,400. 

ISO Setting

There's  an ISO button on the top right panel. You press and rotate the rear control wheel to set the ISO. But unlike most cameras, Auto ISO is activated in a couple of ways, and they're hard to discover without some investigation.

Firstly, there's the TAV mode on the main dial. This is essentially a mode in which you set both the aperture and shutter speed desired, using the front and rear control wheels, and then the camera sets the correspondingly required ISO. You can set both the low and high range settings for Auto ISO in the menu system. This works very well.

In any other shooting mode to activate Auto ISO one presses the ISO button and at the same time the green button on the rear panel. Somewhat unintuatively, to turn Auto ISO off one presses the ISO button and turns the rear control wheel to the left. Not one of Pentax's user interface high points, I must say.

High Dynamic Range

Forest Ravine. Horseshoe Valley, Ontario. August 2014
Pentax 645z with 35mm lens. 1.3 sec @ f/16 @ ISO 100

Mouse-Over Image for Before and After

My studio is not equipped to measure dynamic range. But I'll bet dollars to donuts (isn't that a quaint old phrase) that when DxO Labs publishes their test results the sensor in the 645z will test among the best in this regard.

I discovered the remarkable DR that this camera offers one day early on in my use when shooting a sun-dappled forest scene. The range between highlight spots and shadow areas was at least 10 stops. I did a few test frames to find the extreme highlight exposure, and then just let the shadows fall where they may.

In Lightroom I then used the standard tone controls to open up the shadows and bring the highlights (which were still under 255) into an esthetically pleasing range. What you see in the crop above is my final result. I could have still opened the shadows a bit more, but I wanted a few 0-0-0 areas so as to anchor the image's black level.

The real point here is not that the deep shadows are visible and show detail, but how clean they are. The shot was taken at ISO 100, which means that if my on-the-scene estimate of a 10 stop range is accurate then the deep shadows would need an exposure at about ISO 3200 – 6400 equivalent to be placed in Zone 5 (18% gray). That leaves at least three to four more stops for shadow detail.

Given that in my initial review I wrote that ISO 12,800 shows "visible noise, but no NR needed for printing", I think that both this and my earlier assessment are spot on. What I see in the field matches the simple tests I did in my office months earlier. Now, if you figure that the camera still has some 4 stops of available exposure range, (up to ISO 204,800) though this would make for very noisy deep blacks, there would be detail there. I am therefore confident that when measured by a proper lab the 645z will be shown to have a dynamic range of 13–14 stops, of which 10 or 11 stops are usable without noise reduction. Amazing.

I would go so far as to say that I believe that the sensor in the 645z is currently (September, 2014) the best sensor available in any camera. Yes, Hasselblad and Phase One also use this sensor, but my experience is that Pentax may have figured out how to wring just a bit more performance from this chip, and certainly by comparison its high ISO capability shows this.

Other aspects of sensor performance are best left to lab experts. Using Lightroom 5.6 I am very pleased with colour and tonal rendering. If I felt that I needed something "more" I would make a DNG profile. But nothing that I've seen yet, either skin tones or so-called memory colours seems problematic, so why mess with success?

I should also add that the Pentax 645z's raw files are true 14 bit, unlike many cameras which are 12 bit. This can make a difference in potential image maliability in post processing.

A Note re Lightroom and Profiles

If you use Lightroom to process 645z raw files you should be aware that there seems to be an issue regarding reproduction of reds with the default Adobe "Standard" Profile. Llyod Chambers (Diglloyd) draws attention to this in his 645z report, and indeed it is the case. You are much better off with the embedded profile rather than the Adobe Standard. Camera Calibration / Profile / Embedded.


CMOS Vs. CCD

One of the hoary old myths of the digital world is that CCD sensor technology has some inherent superiority over CMOS when it comes to image quality; colour purity in particular – whatever that is. Well, sorry to burst your balloon, but while this may have been true about ten years ago, it just isn't the case today.

There isn't a CCD sensor on the market that has a wider dynamic range or lower noise than the one that's in the Pentax 645z, and similarly in the Hasselblad and Phase One backs that use the same part. I have shot with all three, and have also owned and worked with virtually every Phase One back from the P25 through the IQ180, and I can tell you that the myth of CCD superiority is just that, a myth.

Is there a difference between backs in terms of colour reproduction? Of course there is. But it is attributable to so many factors, including the A to D converters used, the sensor's particular Bayer filter colour response, delinearization, the maker's special sauce, and also the raw decoder's characteristics and the profile used. 

Sorry you true believers. The CCD ship sailed a while ago, and while some may claim aspects of superiority it's a bit like vinyl record fans bemoaning their fading technology. Yes, I know – some people think that they sound better than anything digital. But what was true of CDs originally (they were truely awful sounding at first) is not at all true for digital sound today. Similarly with CMOS. It's simply time to move on and leave the myths behind.


 

Highlight Warning Disagreement

I will assume that most people interested in an advanced medium format camera understand the principal of ETTR (or Expose to The Right), which is a concept I first wrote about in the early days of digital – following an in depth explanation by Thomas Knoll, one of the inventors of Photoshop and also Camera Raw.

ETTR isn't anywhere as critical today as it was ten or more years ago. Cameras have much more dynamic range and cleaner shadows. But, the so-called 255 brick wall is still there, where the pixel buckets overflow and all detail is lost if too many photons enter the well.

But using ETTR technique is still a very good shooting discipline and can gain you one or two stops of headroom in a shot, and thus up to an extra two stops of DR and cleaner shadow detail in a wide dynamic range situation.

The Pentax 645z has two primary means of showing you the appropriateness of either its selected exposure, or the one that you manually choose. The first is a histogram and the second is highlight blinking. This is available both while shooting (if in Live View) and also in exposure review.

Here's the problem. As with almost all cameras the playback histogram and blinkies are based on an in-camera JPG representation of the image, and the colour space that that camera is set to. If you're set to sRGB you may as well go home and watch TV, because the histrogram will bear little useful relationship to the raw image. The sRGB colour space is so much smaller than the colour gamut of the camera that you'll see highlights shown as blown when you still have two stops of headroom.

If the camera is set to Adobe RBG then you're somewhat better off. Adobe RGB is a larger colour space than sRGB, but still vastly smaller than the camera's colour gamut. So, in a word or two, the playback histogram is fairly useless at indicating overexposure, and if you follow it you will be wasting headroom, and thus have shadow areas that are much noisier than they might be otherwise.

Fortunately the 645z has real-time highlight warning blinkies in Live View mode, and this is taken directly from the sensor. In other words, if something blinks red in Live View it's blown. If it doesn't, it isn't. When displayed along with the histogram in Live View (which also has a red line to the right when anything is blown), you will be able to make technically optimum exposures. (Some experiments have shown that the camera's real-time indication of "blown" coincides almost exactly with that of the histograms in Lightroom or Rawdigger.

I wish though that instead of red blinkies the 645z had adjustable level zebras. They are a more useful and contemporary tool. But more to the point, I would suggest to Pentax that the camera's raw colour space be added alongside sRGB and Adobe RGB for those of us (most of us?) who shoot raw. That way review histograms and blinkies will be more accurate.

Layered Corn
Pentax 645z with 80-160mm f/4.5 @ ISO 1250 

Responsiveness

At 3 FPS the new Pentax 645z has the fastest frame rate of any medium format camera on the market. But there are two annoyances. The first is that it takes a couple of seconds to see an image when shooting in raw, even though there is a big buffer and the camera can keep shooting even while processing.

UPDATE: The instant review time can be cut to less than a second. This trick was told to me by Thomas at http://www.digitalkameraverleih.com/ a Pentax dealer in Vienna. In Camera Menu 4 / Instant Review, turn off Histrogram Display. This will mean than there will not be a Histogram on the instant review, but if you want to see one just press the Play button. You can leave Highlight Alert on. It doesn't delay the image, but just appears a second or so after the image appears.

More annoying is that until the file has been written to the card the two control wheels are unresponsive to changes in aperture or shutter speed. This is something that needn't happen when a camera has such a fast processor, and I believe it could be sorted out in a firmware upgrade if the engineers were mandated to do so.

Out Damn Spot

Dust happens. The 645z can vibrate the sensor to remove dust, and can do so via menu settings on start-up, on shut-down, or on demand. But there is also a very clever mode called Dust Alert. Here, what one does is point the camera at a blank wall or piece of paper and a few seconds later a screen is displayed showing a schmatic representation of the camera's throat and a white screen representing the sensor area, with even the tiniest dust spot shown in black. There is the ability to zoom in and navigate this screen to see what and where the bugger is. Brilliant.

Be aware though then if you do have to clean the 645z's sensor it is located very deep in the camera because of the huge mirror box. An Arctic Butterfly is a good tool for this.

Sunrise Road
Pentax 645z with 80-160mm f/4.5 at ISO 560 

Everything But The Kitchen Sink

There are simply so many controls and modes it would take a huge amount of work to document them all, in which case I might as well write an e-book – which I am not about to do. Instead I'll just touch on a few that I find useful and interesting.

Test Shot

There is a custom function button on the top left shoulder of the camera marked RAW. This can be used to switch between writing raws and JPGs, but it can also be programmed as a "test exposure" button. If you want to see what an image will look like on screen, without necessarily writing a file to disk and then having to delete it (because after all, it's just a test shot), simply press the reprogrammed button marked RAW. Satisfied? Touch the shutter release and the image disappears without being written to a card. Press the AE-L button (you are prompted for this) and you can then save the image to either card #1 or #2, and if you have set these so that one is raw and the other is JPG by doing so you can save the image in either of these formats.

Articulated LCD

If you're not new to the medium format world you'll understand that an articulated LCD is a big deal. This is the first and currently only MF camera to feature one. Very convenient for low level shooting, as DSLR and CSC shooters whose cameras have one will attest.

Separate AF and AE-L Buttons

Ninety percent of the time I shoot almost every camera with the AF function on a rear button. But many cameras link AF and AE-L on a single button and force you to choose between the two. Not the 645z. You have two separate buttons, in quite different locations, though both are handy when either hand-holding or with the camera tripod mounted.

One complaint that I have though is that switching between AF on a button or AF on the shutter release is found in the menu system at Camera / 4 / Button Customization, and there's no short-cut access. I've solved the problem by making shutter activation part of a User Position on the mode dial, but that's not an elegant solution.

Some controls, such as Peaking On and Off can be accessed via a menu shortcut screen when INFO is pressed in shooting mode, and I wish Pentax would add this switch to that screen. There's even some screen available space for it!

Summer Memories
Pentax 645z with 45-85mm f/4.5 @ ISO 100

 Autofocus

One of the sad realities of MF cameras is that most of them have, quite literally, a single focus point. The Pentax 645z has its AF system based on that of their K3 camera, and it's a 27 point phase detection system. But, because it is based on a system from a 35mm camera, on the 645z the focus points are clustered in the center of the image area.

It should also be noted that in Live View mode contrast detection is used, and also, with the exception of a couple of newer lenses most Pentax 645 optics use older style mechanically driven AF motors, and so tend to be slower than contemporary 35mm systems, including Pentax's own.

Information is Power

One of the stand-out features of the 645z is its huge top panel LCD, used in combination with the large and bright articulated rear LCD. Between the two of them the user if presented with a vast array of information, making decisions on how to set various controls a pleasure, especially because so many are activated by single-use buttons and switches.

Shutter Modes

There are so many shutter modes that it is hard to know where to start. Single shot, Cautious Low and High, Self Timer (2 sec and 12 sec), wireless remote single, delayed and continuous, Multi-Exposure with three different composite modes, Interval Shooting and Interval Composite. In other words there's a full intervalometer function built in, and you can stack images on a single frame using several different algorithms. A wealth of capabilities available for those that need them.

Battery Life

I found battery life to be nothing short of phenomenal. Even when shooting with Live View all the time, and with auto-shut-off set to 5 minutes, I can get a couple of days worth of shooting. Batteries are ubiquitous and relatively inexpensive. Two will get you though almost any type of shooting day that you can imagine.

Card Slots / Cards and FLU

The 645z has two SD card slots which can be set independently, or to record in sequence, or with raws to one and JPGs to another.

The camera is designed to take a Eye-Fi card, or better yet Pentax's proprietary though ill-named FLU Card. This card turns the camera into a Wi-Fi device and adds the ability to use just about any web browser (though I found Safari to be preferred, since the latest version of Chrome is broken at the moment with the FLU card). 

Testing with my iPhone 5 I was able not only to view and transfer files, but also to have a live view image on the phone's screen, do touch focus control, and change major parameters such as shutter speed, aperture and ISO. Quite cool, though not something I'm likely to use every day for my work.

I should mention that currently there is no tethering, though Pentax has promised this by the end of the year via the camera's USB3 port.

August Moonset
Pentax 645z with 300mm f/5.6 at ISO 800 

O-GPS1

Just as there is no built-in WiFi, but rather the superior FLU Card, there is no built-in GPS, but a very competent accessory unit called the O-GPS1 is available. This sits in the accessory shoe and communicates with the camera just as you would expect it to, writing GPS data to the appropriate data fields on the images files. The device can also sync your camera's clock to the hyper-accurate GPS time.

But in typical Pentax fashion, there's more. The O-GPS1 has a built in electronic compass which can be called up on the 645z's rear LCD. This is tremendously handy when used on conjunction with a program such as  Photographer's Ephemeris. Knowing exactly where the sun or moon will rise or set and then being able to simply swing the camera to that exact point is a sweet capability. Yes, I know, there are less expensive solutions, but the convenience factor can not be discounted, at least not by me.

Video

Unlike any other medium format camera the Pentax 645z can shoot video. But just as with the dog that can talk, it isn't so much what it has to say, as that it can speak at all. What I mean by this is that the 645z's video is "OK". Except for the fact that it can shoot extremely shallow DOF footage, it offers the usual array of capabilities but nothing special to attract the videgrapher. If the camera had a high quality codec, 4K capability or some other calling card for serious video users, that would create a new market for the camera. But as it is, it's just a nice to have feature that means if the alien mother ship lands across the field, and all you have with you is the 645z, you'll be able to capture footage for the 11 o'clock news. But then again, likely so can your phone.


The Buying Decision and The Value Proposition

No one can tell you how to spend your money (except maybe your spouse or your accountant). But other than those two estimables, you know what you can spend and what difference any given purchase will make to your happiness, your creativity or your productivity – or maybe all three if you're both smart and lucky.

After several days of initial testing, some on-line research, and speaking with previous 645D owners (including my good friend and fellow reviewer Nick Devlin) I decided that the 645z would be an excellent replacement for the Nikon D800e which I had sold a while earlier. Yes, the 645z is bulkier, but the lenses available are inexpensive, very good, and the handling of the 645z is quite superior, for my needs. As a tripod mounted camera (probably 90% of the time) and for my shooting purposes – landscape and nature – and the fact that I regularly make large exhibition quality sized prints, it makes both practical and economic sense. 

For my money, there are two main attractions with the Pentax 645z. The first is the new Sony sourced 50MP sensor, particularly in Pentax's implementation. Pentax seems to have learned how to extract some pretty remarkable high ISO capability from this chip. Having tested and used Hasselblad and Phase One's offerings with this same chip I feel that Pentax's pricing really puts the cat among the pigeons.

Bales and Approaching Storm
Pentax 645z with 80–160mm at ISO 2500 

The second attraction for me is the features and handling offered by the 645z. Pentax just seems to "get it" most of the time when it comes to what a photographer wants to do with their camera (even down to their signature sliding finger opening in their lens shades that allows adjusting a polarizer with the shade attached). Nothing earth shattering, but the kind of photographer-centric design thinking that has earned Pentax a lot of loyal customers over the years.

The next couple of years will tell the tale as to whether my purchase was a good long-term buying decision. But it won't take that long to really put the 645z though its paces. As can be seen from the images on this page, my shooting this August was restricted to just one locale, north-central Ontario farm country.  But, I have a shoot scheduled in Algonquin Park at the end of September, one in Hawaii on The Big Island in December, and two Antarctic workshops, one in January and another in February, 2015. The Pentax system will certainly get a workout in the coming months and I'll let you know eventually how its performed for me.

The Pentax 645Z Can Be Purchased at BH Photo

Michael Reichmann
September, 2014

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