Hands-on: Pentax 645Z medium-format camera

The Pentax 645Z could have other medium-format camera manufacturers looking at its spec sheets and scratching their heads. Despite using the same 51-megapixel sensor as the Hasselblad H5D-50c and the Phase One IQ250 it has faster continuous shooting, can record Full HD video ... and costs considerably less. Gizmag recently went hands-on with the camera to see if it can deliver all that it promises.

There's no getting around it, the Pentax 645Z from Ricoh Imaging is a big camera. It's medium-format big. It has to be, as inside there's a monstrous 43.8 x 32.8 mm 51.4-megapixel AA-filter-free CMOS sensor. That's 1.7 times the size of those in full-frame 35-mm-format cameras. As such, when you first pick up the 645Z – which measures 156 x 117 x 123 mm (6.1 x 4.6 x 4.8 in) and weighs 1,550 g (3 lb 6.7 oz) without a lens – it initially feels positively massive.

But the strange thing is, unlike boxier medium-format cameras, it's easy to forget exactly how big the 645Z is, because it handles much like a DSLR. And this could be key to its success, because it's not intimidating in the way some medium-format cameras can be. Coupled with the price, which isn't that much more than top-of-the-range DSLRs, it's clear the 645Z isn't just for professionals. Pentax even thinks as many as half of 645Z sales could be to well-heeled amateurs.

Everything about the 645Z feels like an oversized DSLR, and it's clear that Pentax has used its know-how from cameras like the K-3 when designing this one. In fact, anyone with experience of using the K Series will feel right at home with a familiar mode dial and core button layout. However, the sheer space available around the camera has also afforded Pentax the ability to incorporate additional physical buttons and controls, including switching dials for changing AF mode, and selecting between stills and movie.

The camera is sturdy like the K-3 too. A die-cast aluminum chassis and magnesium alloy exterior means the camera feels like it could withstand a beating, while 76 seals ensure it's dustproof, weather-resistant and cold-resistant. In fact, the representatives from Pentax gave a wry smile as they actively encouraged us to take the camera out onto the rainy streets of London to test it. It was like they'd arranged the rain, not that it really needs any encouragement here.

Though medium-format cameras are often used on a tripod, the deep hand grip on the 645Z means you don't have to. Depending on the size of the lens you've got mounted, and strength in your arms, it's comfortable to hold. It even feels secure and balanced enough to swing it around in one hand, in the way photographers do … but their camera insurers probably wish they wouldn't.

The optical viewfinder is big and bright and covers 98 percent of that massive frame, making it great for composing shots. The tilting rear 3.2-inch LCD with 1,037k dots also comes into its own for waist-level live-view shooting, or awkward low positions. However, it's a shame that when used in portrait orientation the movement of the screen doesn't help in the same way. While we wouldn't normally criticize this, it is all the more apparent here because the 645Z has two tripod mounts, one on the bottom, and the other on the side.

When it came to performance, it was again obvious that Pentax has brought what it's learnt from its DSLR line-up. A SAXOX 11 autofocus system and 27 AF points (25 cross-type) means that the camera has quick (for a medium-format camera) and accurate autofocus. This is all the more essential with a big sensor, when you can be working with very shallow depth of field. The AF system appeared to work well in the variety of lighting conditions we were able to test it under.

Thanks to its PRIME III image processor, the 645Z is able to offer a much speedier experience than its rivals. In our tests the camera lived up to its claim of delivering continuous shooting speeds of 3 frames per second (for 10 RAW or around 30 JPEGs). While this isn't going to turn the heads of any sports shooters, it's a massive step up in the medium-format world.

Video recording doesn't feel as integrated or complete as modern DSLRs, and Full HD 1080 recording is limited to 60i/50i/30p/25p/24p while HD 720 jumps to 60p/50p. The 645Z also lacks the option for clean HDMI output for external recording, which is now making its way to compacts like the Sony RX100 III. However, having any video option is a big thing for a medium-format camera and the 645Z does have built-in stereo microphones and an optional audio input.

Built-in Wi-Fi is another feature which comes as standard on much lower-level cameras, and feels notably absent from this one. That said, the 645Z has dual SD card slots and is compatible with FLU cards which allow remote access, Live View and shooting controls via wireless LAN. The 645Z also has more traditional tethered shooting options and USB 3.0 connectivity, which we unfortunately were not able to put through its paces.

Because our hands-on was with a pre-production model of the Pentax 645Z, we are understandably not allowed to share any full-resolution files. Indeed, most of our time with the camera was spent seeing how it handled and performed in terms of things like autofocus. When we get the chance to review a final version, we'll hopefully be able to share full image files from the camera.

That said, we can tell you the 645Z delivers the kind of detailed images you would expect from a medium-format megapixel-monster. Even coming from a Nikon D800, the step up in resolution is noticeable and the level of detail captured is immense. The camera also appears to have a good dynamic range and performs very respectably into its higher ISO range.

However, all of this detail comes at a price. And if you are going to use the 645Z in your workflow, you'll need a fair bit of processing power to deal with those 8256 x 6192 pixel images, with RAW DNG files frequently coming in at around the 75MB mark.

All of this brings us to the question of, who is the Pentax 645Z aimed at, and should they buy it? Well, medium-format cameras are not for everyone – they're big, heavy and expensive. This is why they're normally the preserve of professional photographers who spend all their time in the studio. But with the recent adoption of CMOS sensors, the new breed of medium-format cameras are not confined to the studio, and are undeniably where it's at for the ultimate in image quality.

So, while studio and advertising photographers who currently work with medium-format cameras will undoubtedly still make up a large proportion of 645Z buyers, they won't be the only ones to have their heads turned by this camera. The US$8,500 price tag means it's also a viable option for professional photographers who might not need the speed of their current top-of-the-range full frame DSLR, but do want the absolute best image quality available. There's also the advanced (and well off) amateur market which Pentax hopes to draw back into the medium-format fold with this camera, and the now cheaper 645D.

The Pentax 645Z looks to be an incredible camera which could work for a number of photographers in different ways, and with 16 compatible lenses already available, users are not going to be struggling to find the right glass for the job. It really is remarkable to see how Pentax has brought what it's learnt from the DSLR market to the medium-format game.

The 645Z is faster, more versatile, and more affordable at launch than comparable cameras which have gone before it. The fact it's been released appears to show that Pentax believes there's a bigger market for medium-format cameras than is currently being served, now it just remains to see if photographers agree.