The 645Z is Pentax’s first medium-format camera with a CMOS sensor. The camera offers more than 51-MP resolution and many professional features, but its handling is as easy as using a standard SLR.
Comments on Image Quality
Colour: The Pentax 645Z reproduced our colour test chart very well, with nearly perfect saturation (98.2 percent). The automatic white-balance system created a minor shift of brighter nuances into the yellow area, but this effect is really insignificant. The colour errors are on a very low level. Skin tones are reproduced very naturally; all other colours show no to only minor aberrations.
Sharpness: The Pentax 645Z created images with a sharp, crisp look, but couldn’t completely reach its nominal sensor resolution of 6192 lines per picture height. But a maximum result of 5671 lines per picture height is still extremely high and offers a lot of “resolution buffer” for large-format prints or printing extracted parts of the images. This will be helpful for product shots as well as architectural photography, for example.
The Pentax 645Z shots have a very natural-looking sharpness. The portrait shot has a slightly softer look than the test box shot, which is really crisp, but doesn’t show typical sharpness filtering artifacts like contours on contrast lines for example.
Noise: The camera uses a 43.8 x 32.8-mm sensor with 51 MP and therefore a pixel size of 5.3 microns. This is similar to the pixel size of the Phase One iQ250 digital back or the Hasselblad HSD-50C, which uses a slightly different sensor. The pixel size and its CMOS technology allow one to shoot with higher ISO speed ratings than former CCD digital backs. The Pentax 645Z allows for shooting with ISO 208,400, but using this extreme ISO mode isn’t recommendable because the camera shows extreme luminance and colour noise artifacts in these images. The noise results are really good in lower ISO speed settings. Between ISO 100 and 3200 they are a little bit higher than in images taken with full-frame-sensor cameras made by Canon, Nikon and Sony, but still quite good.
The Pentax 645Z achieved high results in our dynamic range test. The maximum of 12.3 f-stops is really an extreme result. High dynamic range results are captured in ISO 100 to ISO 6400 mode. In higher modes it drops significantly. In modes higher than 51,200, it declines to less then 8 f-stops.
Comments on Handling
Ricoh Imaging presented a new Pentax medium-format camera with a CMOS sensor. The dimensions of this sensor are 43.8 x 32.8 mm—1.66 times the size of a standard full-frame sensor with 36 x 24 mm. Nevertheless Pentax still doesn’t offer a full-frame sensor camera, so there is a gap between the K-series with APS-C-sized sensors and the new medium format 645Z.
The new Pentax 645Z uses a sensor with a very high resolution. It offers up to 51.4 MP (8.265 x 6.192 pixels) and is therefore a camera for all photographers who need high-resolution images (architecture, high-quality product shots for advertising etc.) The camera is able to record JPEGs and saves raw images in Pentax’s own PEF format and in Adobe’s DNG format.
The Pentax 645Z has a very massive, robust body. The sensor, mirror box and pentaprism for the optical viewfinder are large and require a lot of space, so they are the main reason for the bulky and massive design of medium-format cameras.
The body of the Pentax 645Z is sealed; it can be used in rainy situations on an outdoor shooting. Despite its bulkiness the camera handles well: the large grip on the right-hand side allows one to hold the camera comfortably. A lot of function buttons and set-up dials make it easy to change image parameters while holding the camera in its shooting position.
For images taken in portrait (upright) format, the camera offers a 3/8-inch tripod socket on its left-hand side to mount it on a tripod.
It should be very easy for Pentax photographers to handle the new 645Z. The whole set-up and the menu structure are very similar to the Pentax K series, so photographers will immediately be able to work with this new medium-format camera.
The camera offers a large and bright viewfinder, which offers full control of the image. Manual focusing is easy, even though the large image format will cause a very shallow depth of field. The camera has a swivel monitor. The Pentax 645Z is the first medium-format camera capable of shooting videos. It is able to record Full HD videos.
+ professional medium-format system with a lot of current camera features
+ very large and bright optical viewfinder with 100-percent field of view
+ very high-resolution images
+ very realistic colour reproduction (white balance system is very precise)
+ fast AF system
+ easy handling, easy for Pentax photographers who want to switch from 35-mm SLRs to medium format
+ video recording features
+ swivel monitor
– disappointing video results
This review is based on precise lab tests conducted by BetterNet GmbH and provided by the Technical Imaging Press Association (TIPA). TIPA is the largest family of independent photo and imaging magazines worldwide. Photo Life is an active member of TIPA.
|SPEC SHEET: Pentax 645Z|
|BASIC TECHNICAL DATA:|
|Resolution||8265 x 6192|
|Colour depth (in bits)||42|
|Size of sensor (in inches)||0/0.00|
|Size of sensor (in mm)||43.8 x 32.8|
|Focal length (wide angle; 35-mm equivalent; in mm)||44|
|Focal length (tele; 35-mm equivalent; KB in mm)||44|
|Focal length (wide angle; real; in mm)||55.0|
|Focal length (tele; real; KB in mm)||55.0|
|Speed||2.8 – 2.8|
|Macro||50 – 100|
|Manual focus, controlled by function elements||no|
|Manual focus, controlled with lens ring||yes|
|Start-up time (in sec)||0.15|
|Shutter delay (in sec) without pre-focusing||0.15|
|Shutter delay (in sec) with pre-focusing||0.01|
|Continuous shooting speed (frames per second)||3.0|
|Max. burst during continuous shooting speed||12.0|
|Fastest shutter speed (in sec)||1/4000|
|Long-time exposure/shutter speed (in sec)||30|
|aperture pre-setting, shutter-speed pre-setting, manual exposure settings,|
|automatic bracketing, time-lapse photography|
|Individual white balance||yes|
|Manual ISO control||yes|
|Standard file formats:||JPEG, RAW, DCF|
|JPEG compression grades:||3|
|LCD AND PREVIEW:|
|Size (in inches)||3.2|
|Resolution of LCD (in pixels)||103700|
|Zoom mode during preview||yes|
|Index during preview||yes|
|Slideshow during preview||yes|
|Battery charger included||yes|
|Power supply unit||no|
|Supported memory cards||SD card, SDHC card, SDXC card c|
|PC connection||USB, HDMI|
|TV out||PAL/NTSC HDMI|
|Dimensions (width x height x depth; mm)||156 x 117 x 123|
|Weight (body without battery and memory card; in g)||1550|
|Manual on CD||yes|