Pentax 645Z

Pentax 645Z

51.6MP medium-format CMOS sensor | ISO 100-204800 | 1080/60i video

What we like:

  • Best image quality at base ISO of any camera we've tested
  • Affordable for medium format camera
  • Articulating LCD

What we don't:

  • Autofocus system is fairly basic relative to 35mm competition
  • Imprecise AF, especially with old 645 lenses
  • Bulky and heavy

While the Canon 5DS R takes its place as the world's highest resolution full-frame DSLR, if you remove the full-frame qualifier it suddenly drops off the top spot. The Pentax 645Z houses a 51.6MP CMOS sensor that measures roughly 44x33 mm. It's not 'full-frame' with respect to medium format, but the larger sensor area does mean more light is gathered than comparable full-frame 35mm DSLRs. More light means crisper images and less noise (you can't beat physics), and our studio scene shows the 645Z slightly edging out full-frame competitors at both base ISO and all but the highest ISOs.

The 645Z feels quite familiar if you're coming from a Pentax DSLR. For a medium format camera, it's reasonably-sized and well-balanced, though you won't want to carry it around all day or on a hike. The 645Z is truly the studio photographer's affordable medium format option. In a controlled setting, the camera is capable of amazing image quality. 51.6MP resolution is a lot to work with, allowing for detailed enlargements. Arguably more important, it's the first time we're seeing a 'modern' low-noise sensor in a medium format camera, which allows the format to reach nearly its full potential. Previous medium format offerings had severely compromised sensor performance that placed their dynamic range and high ISO performance below smaller sensor formats. The 645Z breaks this mold and slightly edges past all 35mm full-frame performance with respect to dynamic range, and most with respect to low light, high ISO performance. There's a reason this sensor is now shared across a number of medium format cameras.

"You can't beat physics: more light means crisper images and less noise, and our studio scene confirms the 645Z to edge out full-frame competitors at both base and all but the highest ISOs."

In less controlled shooting scenarios, you may find autofocus performance frustrating, especially if you are coming from a high-end DSLR or advanced mirrorless. There are 27 very centrally located AF points. Although most of these are cross-type and sensitive down to -3EV, with 3 central points capable of higher-precision with F2.8 lenses, overall AF experience is slow with most lenses. Subject recognition and tracking is extremely limited, both by the confinement of the AF points to the center of the frame, and also by a seemingly limited ability of the 86,000-pixel RGB metering sensor to properly understand and follow your subject based off of scene analysis. All that said, the AF system is quite advanced compared to most medium format competitors.

The 645Z is also video capable, a medium format first. It can capture up to 1080/30p (60i) and offers a built-in stereo mic, as well as an external mic jack. Users can also control audio levels. We have not had a chance to used the 645Z for video capture, and frankly, it seems like a bit of an odd choice to use in such manner, but it's still nice to see it included.

Ultimately when used with patience, and with attention paid to good technique (mirror up, tripod, and the like), the results from the 645Z are some of the best on this side of $10000. But if casual usability is a need, there are options that allow much more focus on the decisive moment without careful planning.

Studio Test Scene | Specifications Compared

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