Make no mistake about it, the Pentax 645Z ($8,499.95) from Ricoh Imaging is a serious medium format camera that can go toe-to-toe with vastly more expensive models in terms of image quality. It uses the same image sensor as the Phase One IQ250 and Editors' Choice Mamiya Leaf Credo 50 , but while both of those products are modular backs that can be used with medium format and large format technical cameras alike, the 645Z offers a more refined shooting experience that comes with an integrated sensor and body design.



The Pentax does has some shortcomings as a studio camera, notably the lack of modern leaf-shutter lenses with which to pair it, but its image quality is just as good as the competing models that cost more than $25,000, and its autofocus system far surpasses that of the 645DF+ body that the Mamiya and Phase One offerings are most often paired. When you factor in its price, it's an easy pick as our Editors' Choice for medium format systems. If your workflow does require a modular back or high-speed sync with studio strobes, the Mamiya Leaf Credo 50 is a fine alternative, but it's one that costs more than three times as much.

Design and Controls

The 645Z ($5,023.51 at Amazon) looks a lot like the company's first medium format digital effort, the 645D . It's a big, boxy SLR with a deep handgrip, measuring in at 4.6 by 6.1 by 4.8 inches (HWD) with a hefty 3.4-pound weight. The body is a bit bulky due to the big mirror and eye-level viewfinder that go hand-in-hand with a medium format image sensor, so Pentax has opted to incorporate dual tripod mounts; one on the bottom of the camera for landscape shooting and another on the left side for portrait orientation. I found that the design handles well, even when working handheld, although it's noticeably deeper than the Leica S-E (Typ 006) (4.7 by 6.3 by 3.3 inches, 2.8 pounds), a medium format camera that's styled more like a traditional 35mm SLR.

Even though the 645Z uses the same Sony-made CMOS image sensor as the Mamiya Leaf Credo 50 and Phase One IQ250, Pentax has implemented in a way to squeeze just a little bit more resolution out of it—51 megapixels instead of 50. When you've got a camera that's capable of recording images with that amount of detail, it's not a huge difference. The sensor is a CMOS design, so its ISO sensitivity can be pushed higher than CCD image sensors that are found in other medium format bodies, including the Pentax 645D, which is still in production at a lower price point, and the Leica S-E (Typ 006).



The image sensor is 33 by 44mm in size, larger than the 24-by-36mm sensors found in full-frame cameras and the 16-by-24mm images utilized by APS-C format cameras. A larger sensor has more advantages than just a higher pixel count—after all, the full-frame Nikon D810 packs 36 megapixels, which is comparable to some medium format cameras in terms of pure resolution. A lens that would act as a medium telephoto on a full-frame sensor, like the HD D FA 645 Macro 90mm F2.8 ED AW SR ($1,999.00 at Adorama) captures a wider field of view on the 645Z, equivalent to a 70mm lens on a full-frame system. If you frame the same shot at 70mm on the Nikon D810 and at 90mm on the 645Z at the same aperture you'll see that the image captured by the 645Z has a shallower depth of field and a slightly flatter perspective. The large image sensor is one of the reasons that landscape photographers move toward medium format; it's possible to capture wide vistas with a lens that would only be a moderate wide-angle on full-frame systems.



Ricoh has used the ample body space to its fullest, placing physical controls to adjust settings at your fingertiips. The handgrip houses a control dial, the power switch, and shutter release. Moving the power switch beyond the On position activates depth of field preview, which stops down the lens to the shooting aperture so you have an idea of what will be in focus in your photo. On the right side of the mirror box there's a switch to engage Mirror Lock-Up, which activates a two-stage shutter release—pressing the shutter button raises the mirror, and pressing it a second time captures an image. This is useful when you're working on a tripod and wish to eliminate the vibration introduced by 645Z's big mirror flapping up and down when capturing an image.



A row of buttons adorns the top plate, to the left of the hot shoe. The Raw button quickly toggles between JPG and Raw+JPG, or Raw and Raw+JPG shooting. Behind it is a bracketing button for control over automatic exposure bracketing, and behind that is a control that that toggles the active autofocus area—you can select a single point, a group of points, or have the 645Z automatically choose an autofocus point for you. Finally there's the Lock button, which allows you to lock down settings so that you don't accidentally adjust the shutter speed or aperture when in the middle of a shoot.



There's a standard mode dial, which will be familiar to SLR shooters, angled on the top plate, to the left of the eyepiece. All of the modes are self-explanatory except TAv and Sv, which are fairly unique to Pentax. TAv allows you to set the shutter speed and aperture manually, letting the camera select an ISO speed for a proper exposure. This is something that has been in Pentax cameras for years, and other manufacturers have copied it by allowing you to use Manual mode with automatic ISO control, but Pentax opts to give it its own dial position. That means that, when you switch over to Manual, you won't have the option of automatic ISO control.



Sv, Sensitivity Priority, allows you to select the ISO and have the camera control the other settings. It's not something I ever use, but it could be useful if you want to push the ISO high to ensure that your images have a grainy look. The dial is locking, so you'll have to depress the center button while turning it, but that means it's almost impossible to accidentally change the shooting mode. Below the dial is a metering control wheel that quickly switches between average metering over the entire frame, center-weighted metering, and spot metering.



To the right of the eyepiece there's a big monochrome LCD that shows all of the current shooting settings. It's backlit; there's a button that activates the light to its right. Ahead of it there are two buttons; one adjusts the exposure compensation value (from -5 to +5 EV in third-stop increments) and another that sets the ISO. These sit directly behind the shutter release. Setting the ISO via the control button and rear command dial locks it into a set value, but it's a simple matter to switch to automatic ISO control if that suits your shooting style: just hold down the ISO button and the green button (located on the rear, below the command dial) at the same time.



Other rear controls include an AE-L button to lock exposure, and a dedicated AF button. There's a four-way controller with a center OK button; its directional controls adjust the drive mode, JPG color output settings, flash settings, and the white balance. A button that sets the active focus point is located just below the four-way controller. Playback and delete controls are located on the rear, as is a Record button, which toggles Live View mode when the 645Z is set to capture still images. A toggle switch changes between still and video mode—it's located just to the right of the viewfinder—and to the left of the viewfinder there's another switch that changes between AF-S and AF-C focus.



Features and Tethered Workflow

The camera utilizes a focal plane shutter, which can fire at 1/4,000-second at its shortest duration. But if you're syncing with an external strobe, like studio lights that are often utilized by medium format shooters, the minimum shutter speed is limited to 1/125-second. Pentax doesn't currently make any leaf shutter lenses for the 645 system—there are a pair of older, fully manual lenses available on the used market. If you seek out those lenses you can sync at 1/500-second, but modern leaf shutter lenses for other systems, including the Phase One and Mamiya medium format system, can sync at speeds as fast as 1/1,600-second.



At slower sync speeds you can set the flash to fire as the shutter curtain opens or as it closes, but only if you're using a P-TTL flash. If you're shooting with a non-dedicated flash or with studio lights controlled via a sync cable or wirelessly via a PocketWizard ($87.22 at Amazon) , the 645Z is limited to first-curtain flash sync.



The rear LCD is mounted on a hinge, making it possible to frame images from above or below when working in Live View mode. It's a 3.2-inch LCD with a 1,037k-dot resolution. The display is plenty sharp, and it's bright enough for use on outdoors without issue. It's not a touch screen like you'll find on Phase One and Mamiya backs, and it's not quite as quick to zoom images to 100 percent to confirm critical focus. With the Credo 50 you can simply double tap the touch screen and zoom to 100 percent; with the Pentax you'll need to use the rear control dial to zoom into the image, and the rear four-way controller to move away from its center.



The viewfinder is a solid glass trapezoid prism. It's noticeably larger than the viewfinders you'll find in even the best full-frame D-SLRs, but it doesn't precisely cover the frame. The finder offers 98 percent coverage, which is pretty close and leaves some wiggle room for prints and crops, but you'll want to use the rear LCD if you want to get a precise idea of your frame. The viewfinder has a diopter adjustment, so you can adjust it to match your eyesight.



There's an in-camera intervalometer to capture sequences of stills over a set amount of time. Images can be saved individually (up to 2,000 shots, with any time between 2 seconds and 24 hours between each capture), or automatically compiled into a movie. The duration of the movie varies based on the time between shots, with movie lengths of about 17 minutes up to 99 hours available. Time-lapse videos can be saved at 1080p or 4K resolution, but there's no in-camera flicker reduction like you'll find in Nikon cameras with similar functionality. On the other hand, the Nikon cameras can't create 4K video in-camera.

There's no built-in Wi-Fi, but the 645Z does work with the Pentax FluCard Pro ($99.95), a 16GB memory card that supports remote file transfer and camera control via a Web browser. The FluCard must be used in the secondary memory card slot, and since you can only transfer JPG photos, it's not a bad idea to set the primary card slot for Raw capture and the secondary slot for JPG capture when using it. If you have an image shot in Raw format that you wish to transfer you can always convert it to JPG in-camera via its integrated Raw development toolset.



The browser approach eliminates the need for a dedicated app, so you can take control of the 645Z even if you're using a laptop, or a platform like Windows Phone that doesn't enjoy as much app support as iOS and Android. It broadcasts its own network SSID; you can set the network name and password via your browser. When using the FluCard to control the 656Z remotely you'll have access to a basic control mode that lets you tap to select a focus point and fire the shutter. You can switch this to advanced mode, which gives you more control, including the shutter speed, aperture, exposure compensation, and ISO. The Live View feed is fairly smooth, with just a little bit of lag at times.



Studio shooters prefer the speed and reliability that wired tethering provides. Unfortunately, the standard desktop app for tethered capture, Phase One Capture One Pro, doesn't support the 645Z. This isn't due to a technical limitation—the DNG file format in which the 645Z shoots is supported when using other cameras with Capture One Pro. Alex Munoz, a photographer using the 645Z for professional work, has written a tool that strips EXIF data from 645Z files so that they can be edited in Capture One Pro. However, that doesn't address tethered shooting.



Ricoh doesn't include tethering software with the purchase of a 645Z. If you need that functionality, you'll need to spend another $200 on the Pentax Image Transmitter 2 application. The software works with Windows and Mac systems and offers full control over the 645Z. I tested the Mac version and found that it worked very well. The 645Z connects via USB 3.0 and, as long as it is set to PTP mode via the camera menu, the software reconizes the camera immediately. You've got full control over settings, depending on which mode the 645Z is set to, and you can initiate Live View, which is prefereable for most studio work. It's possible to click an area of the frame to focus or to focus and fire; just keep in mind that the focus area doesn't cover the outer third of the frame. When you're shooting with the camera in the field there's a frame that shows you the limit of the focus system, but it's not there in the software. Adding that mask would be an easy update and a welcome addition to the software. It is possible to magnify the area outlined by the focus box to confirm that the autofocus has nailed the shot or as a manual focus aid. But even when the camera is set to focus manually, there's no way to magnify the an area of the frame that is outside of the supported autofocus area.

Images transfer automatically to a folder that you set in the sofware. You can select which file formats to transfer, and you can also save to an internal memory card if desired. The transfer is nearly instant, and if you set up a watched folder in Lightroom they'll automatically show up in your catalog. And, while there's no way to tether directly with Capture One Pro, you can use Alex Munoz's tool to strip EXIF data and then import into Capture One. The software works well, and aside from adding a focus mask and the ability to magnifiy any part of the frame, there aren't any serious improvements that seem necessary for tethered studio work. My only real complaint is cost; $200 isn't a huge price to pay for the functionality, but it's something that should be included with the purchase of the camera.

Performance and Conclusions

The 645Z is a speed demon when compared with other medium format system cameras. It can start, focus, and fire in just under a second—the Mamiya Credo 50 requires 13.3 seconds to do the same. Once it's on it can fire off shots continuously at 2.9 frames per second. It can keep up that pace for 11 Raw or Raw+JPG captures, or 37 JPG shots. The Credo 50 is slower from shot to shot, managing just 1.1fps.

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The camera uses a 27-point autofocus system, the same one you'll find in the APS-C Pentax K-3 ($1,085.95 at Adorama) . Because of this the points are clumped together in the center area of the frame. There's still a lot more control available over the focus point as you'll find in other medium format systems that feature less advanced autofocus systems—the Mamiya 645DF+ that is often paired with Mamiya and Phase One backs has left, center, and right points, but there's no indication in the viewfinder as to their precise location. With the 645Z a red dot shows you the precise focus point.



There is one not-so-obvious downside to the relatively small focus area—if you set the exposure point to be weighted to the focus point in the camera menu, your exposures will always be somewhat center-weighted when using the optical viewfinder. It's a feature that I almost always enable with Pentax SLRs, but I skipped doing so with the 645Z. I found it easier to simply vary between average, center-weighted, and spot metering, opting for center-weighted when I wanted to give emphasis to the exposure around the focus point. The exception to this is Live View; you can move the active focus point to the outer edges of the frame when working in Live View, and it may be beneficial to tie the exposure to the focus point when you have access to the larger focus area that Live View provides.



In terms of autofocus speed, the 645Z is fairly snappy. In bright light it locks and focuses in less than 0.1-second, but it does slip to 0.6-second to do the same in dim conditions. When using Live View in bright light the camera locks and fires in 0.9-second, but it can slow to 4.4 seconds in dim conditions. The only time I felt let down by the autofocus system was when trying to keep up with a fast-moving toddler; it's more than adequate for landscape and studio work. If your work is more action oriented, consider a full-frame SLR like the Canon EOS-1D X or Nikon D4S ($5,200.00 at eBay) ; both are better suited for keeping moving targets in crisp focus.



The amount of detail that the 51-megapixel image sensor is able to capture is incredible. I used Imatest to check the sharpness of images that the 645Z captures when paired with the SMC D FA 645 55mm F2.8 AL (IF) ($999.98 at Amazon) . At f/2.8 the lens scores 2,939 lines per picture height on a center-weighted sharpness test when paired with the 645Z; resolution increases as the lens is stopped down, peaking at 3,577 lines at f/11. The extra resolution that the sensor provides gives the 645Z a distinct advantage over the 40-megapixel 645D. The 55mm lens shows 2,325 lines on the 645D at f/2.8, and is limited to 2,544 lines at f/11.



High ISO performance is another area in which the 645Z runs circles around comparable cameras. I set the 645Z's picture processing settings to default, including using default noise reduction, and ran the JPG output through Imatest to check and see how well noise was controlled. The 645Z keeps noise under 1.5 percent through ISO 25600 when using these settings. Close examination of the images from our ISO test sequence on a calibrated NEC MultiSync PA271W display does show that there's a loss of detail at ISO 25600. Images look better at ISO 12800 and 6400, but you'll need to dial down to ISO 3200 to get the default JPG output to show as much detail as the Raw images capture. The converse is true when you push the ISO higher; images are a bit blurry at ISO 51200 and continue to degrade through the top ISO 204800 sensitivity.



But if you're shooting with this camera, you're probably going to work with Raw images. I developed DNG files from the camera in the latest version of Lightroom using default develop settings. There's some noise at ISO 25600, but it's not offensive and detail is still strong. There's some loss of detail at ISO 51200, but I wouldn't hesitate to push the camera that far if a shot required it. Noise starts to overtake detail at ISO 102400, but it's not until you push all the way to ISO 204800 that noise really kills image fidelity. There are pixel-level crops included in the accompanying slideshow, so you can judge how the camera holds up for yourself.



In addition to 4K time lapse, the 645Z can capture QuickTime 1080p HD video at 24, 25, or 30fps, 1080i footage at 50 or 60fps, or 720p video at any of those frame rates. The footage is crisp, but it's not without issue. If you enable the digital image stabilization it appears to shimmer a bit, and rolling shutter is evident even during modest camera movements, giving footage a jelly-like look. The 645Z is a still camera that happens to have a video mode; don't expect to use it for serious video work. As of now it's the only medium format camera out there that captures video, but the Leica S (Typ 007) ($25,400) is set to join it when it's released this spring. The Leica will record 1080p footage using the entirety of the sensor, and will also capture 4K footage using an APS-C crop mode.



There are a number of interface ports built into the 645Z. A wired remote control port is located on the right side, just below the strap lug. Additional ports are located on the left and include a DC power input, a micro HDMI port, a USB 3.0 port, a microphone input, and dual SD/SDHC/SDXC memory card slots.



Like most medium format cameras, the Pentax 645Z isn't one that you'll reach for when shooting fast action. But for studio work, landscape photography, and other disciplines that don't require high frame rates and advanced tracking autofocus, it's a phenomenal camera. The look that medium format delivers can't be easily matched by full-frame and other small format systems, and it's tough to argue with the 645Z's go-anywhere design and aggressive price point. It's an easy pick as our Editors' Choice for medium format systems, as it punches well above its weight and produces some of the best images you'll find in any digital camera. There are reasons to spend more on a medium format system—the Mamiya Leaf Credo 50 is a better choice if you absolutely need a modular digital back or if leaf shutter lenses are a must, and even though it's priced at close to $27,000, it's the most affordable digital back on the market with a CMOS image sensor. But if you don't need that functionality, and you want to shoot medium format, the Pentax 645Z is the camera to get.



Artboard Created with Sketch. Pentax 645Z 4.5 Editors' Choice See It $5,023.51 at Amazon MSRP $8,499.95 Pros Captures images at 51-megapixel resolution.

Excellent high ISO performance.

Speedy response.

2.9fps continuous shooting.

27-point autofocus system.

Articulating rear display.

Weather-sealed design.

Solid control layout.

Dual tripod mounts.

Optional Wi-Fi via FluCard memory card.

1080p video and 4K time-lapse.

Competitive price point. View More Cons System lacks modern leaf-shutter lenses.

Autofocus can struggle with fast moving subjects.

Focus points grouped tightly in center of frame.

Integrated design lacks versatility of a modular back.

So-so video quality.

Tethered shooting software not included. View More The Bottom Line The Pentax 645Z offers the incredible resolution and large sensor of a medium format system at a price that's a third that of the competition. It's an easy pick for our medium format Editors' Choice camera.

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