Pentax 645Z versus Sony A7R II
The Pentax 645Z and the Sony Alpha A7R II are two digital cameras that were revealed to the public, respectively, in April 2014 and June 2015. The 645Z is a DSLR, while the A7R II is a mirrorless interchangeable lens camera. The cameras are based on a medium format (645Z) and a full frame sensor. The Pentax has a resolution of 51.1 megapixel, whereas the Sony provides 42.2 MP.
An illustration of the physical size and weight of the Pentax 645Z and the Sony A7R II is provided in the side-by-side display below. Three successive views from the front, the top, and the rear are shown. All width, height and depth dimensions are rounded to the nearest millimeter. You can also toggle the display to switch to a percentage comparison if you prefer that the measures are being expressed in relative terms (in this case, the camera on the left side – the 645Z – represents the basis for the calculations across all the size and weight measures).
If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7R II is considerably smaller (60 percent) than the Pentax 645Z. Moreover, the A7R II is substantially lighter (60 percent) than the 645Z. In this context, it is worth noting that both cameras are splash and dust-proof and can, hence, be used in inclement weather conditions or harsh environments.
The above size and weight comparisons are to some extent incomplete since they do not consider the interchangeable lenses that both of these cameras require. Hence, you might want to study the specifications of available lenses in order to get the full picture of the size and weight of the two camera systems.
The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. If you want to switch the focus of the display and review another camera pair, just select a new right or left comparator from among the camera models in the table. Alternatively, you can also move across to the CAM-parator tool and choose from the broad selection of possible comparisons there.
|Camera Body Specifications
|Pentax 645Z (⇒ rgt)||156 mm||117 mm||123 mm||1550 g||650||YES||2014||8,499||latest||check|
|Sony A7R II (⇒ lft)||127 mm||96 mm||60 mm||625 g||290||YES||2015||3,199||discont.||check|
|Canon 5DS R (⇒ lft | rgt)||152 mm||116 mm||76 mm||930 g||700||YES||2015||3,699||latest||check|
|Canon 5DS (⇒ lft | rgt)||152 mm||116 mm||76 mm||930 g||700||YES||2015||3,699||latest||check|
|Hasselblad X1D (⇒ lft | rgt)||150 mm||98 mm||71 mm||725 g||..||YES||2016||8,995||latest||check|
|Leica SL (⇒ lft | rgt)||147 mm||104 mm||39 mm||847 g||400||YES||2015||7,450||latest||check|
|Nikon D750 (⇒ lft | rgt)||141 mm||113 mm||78 mm||750 g||1230||YES||2014||2,299||latest||check|
|Nikon D810 (⇒ lft | rgt)||146 mm||123 mm||82 mm||980 g||1200||YES||2014||3,299||discont.||check|
|Nikon D4S (⇒ lft | rgt)||160 mm||157 mm||91 mm||1350 g||3020||YES||2014||6,499||discont.||check|
|Pentax 645D (⇒ lft | rgt)||156 mm||117 mm||119 mm||1480 g||800||YES||2010||9,995||discont.||check|
|Sony A7R III (⇒ lft | rgt)||127 mm||96 mm||74 mm||650 g||650||YES||2017||3,199||latest||check|
|Sony A99 II (⇒ lft | rgt)||143 mm||104 mm||76 mm||849 g||490||YES||2016||3,199||latest||check|
|Sony A7S II (⇒ lft | rgt)||127 mm||96 mm||60 mm||627 g||370||YES||2015||2,999||latest||check|
|Sony RX1R II (⇒ lft | rgt)||113 mm||65 mm||72 mm||507 g||220||no||2015||3,299||latest||check|
|Sony A7 II (⇒ lft | rgt)||127 mm||96 mm||60 mm||599 g||350||YES||2014||1,999||latest||check|
|Sony A7S (⇒ lft | rgt)||127 mm||94 mm||48 mm||489 g||380||YES||2014||2,499||discont.||check|
|Sony A7R (⇒ lft | rgt)||127 mm||94 mm||48 mm||465 g||340||YES||2013||2,299||discont.||check|
The listed prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The A7R II was launched at a markedly lower price (by 62 percent) than the 645Z, which puts it into a different market segment. Usually, retail prices stay at first close to the launch price, but after several months, discounts become available. Later in the product cycle and, in particular, when the replacement model is about to appear, further discounting and stock clearance sales often push the camera price considerably down. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.
The size of the imaging sensor is a crucial determinant of image quality. All other things equal, a large sensor will have larger individual pixel-units that offer better low-light sensitivity, wider dynamic range, and richer color depth than smaller pixels in a sensor of the same technological generation. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to isolate a subject from the background. On the downside, larger sensors are more costly to manufacture and tent to lead to bigger and heavier cameras and lenses.
Of the two cameras under consideration, the Pentax 645Z features a medium format sensor and the Sony A7R II a full frame sensor. The sensor area in the A7R II is 40 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 0.79 and 1.0. The sensor in the 645Z has a native 4:3 aspect ratio, while the one in the A7R II offers a 3:2 aspect.
With 51.1MP, the 645Z offers a higher resolution than the A7R II (42.2MP), but the 645Z nevertheless has larger individual pixels (pixel pitch of 5.30μm versus 4.52μm for the A7R II) due to its larger sensor. However, the A7R II is a somewhat more recent model (by 1 year and 1 month) than the 645Z, and its sensor might have benefitted from technological advances during this time that enhance the light gathering capacity of its pixels. Coming back to sensor resolution, it should be mentioned that neither of the two cameras has an anti-alias filter installed, so they are able to capture all the detail the sensor resolves.
Consistent information on actual sensor performance is available from DXO Mark for most cameras. This service is based on lab testing and assigns an overall score to each camera sensor, as well as ratings for dynamic range ("DXO Landscape"), color depth ("DXO Portrait"), and low-light sensitivity ("DXO Sports"). The Overall DXO ratings for the two cameras under consideration are close, suggesting that they provide similar image quality. The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.
|Pentax 645Z (⇒ rgt)||Medium Format||51.1||8256||6192||1080/60i||26.0||14.7||4505||101|
|Sony A7R II (⇒ lft)||Full Frame||42.2||7952||5304||4K/30p||26.0||13.9||3434||98|
|Canon 5DS R (⇒ lft | rgt)||Full Frame||50.3||8688||5792||1080/60p||24.6||12.4||2308||86|
|Canon 5DS (⇒ lft | rgt)||Full Frame||50.3||8688||5792||1080/60p||24.7||12.4||2381||87|
|Hasselblad X1D (⇒ lft | rgt)||Medium Format||51.3||8272||6200||1080/25p||26.2||14.8||4489||102|
|Leica SL (⇒ lft | rgt)||Full Frame||24.0||6000||4000||4K/30p||25.0||13.4||1821||88|
|Nikon D750 (⇒ lft | rgt)||Full Frame||24.2||6016||4016||1080/60p||24.8||14.5||2956||93|
|Nikon D810 (⇒ lft | rgt)||Full Frame||36.2||7360||4912||1080/60p||25.7||14.8||2853||97|
|Nikon D4S (⇒ lft | rgt)||Full Frame||16.2||4928||3280||1080/60p||24.4||13.3||3074||89|
|Pentax 645D (⇒ lft | rgt)||Medium Format||39.5||7264||5440||no||24.6||12.6||1262||82|
|Sony A7R III (⇒ lft | rgt)||Full Frame||42.2||7952||5304||4K/30p||26.0||14.7||3523||100|
|Sony A99 II (⇒ lft | rgt)||Full Frame||42.2||7952||5304||4K/30p||25.4||13.4||2317||92|
|Sony A7S II (⇒ lft | rgt)||Full Frame||12.0||4240||2832||4K/30p||23.6||13.3||2993||85|
|Sony RX1R II (⇒ lft | rgt)||Full Frame||42.2||7952||5304||1080/60p||25.8||13.9||3204||97|
|Sony A7 II (⇒ lft | rgt)||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
|Sony A7S (⇒ lft | rgt)||Full Frame||12.0||4240||2832||1080/60p||23.9||13.2||3702||87|
|Sony A7R (⇒ lft | rgt)||Full Frame||36.2||7360||4912||1080/60p||25.6||14.1||2746||95|
Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the A7R II provides a better video resolution than the 645Z. It can shoot movie footage at 4K/30p, while the Pentax is limited to 1080/60i.
Beyond body and sensor, cameras can and do differ across a range of features. For example, the A7R II has an electronic viewfinder (2400k dots), while the 645Z has an optical one. Both systems have their advantages, with the electronic viewfinder making it possible to project supplementary shooting information into the framing view, whereas the optical viewfinder offers lag-free viewing and a very clear framing image. The adjacent table lists some of the other core features of the Pentax 645Z and Sony A7R II along with similar information for a selection of comparators. The full specs-sheets can be found in the camera manual or, for example, in the dpreview camera hub.
|Pentax 645Z (⇒ rgt)||optical||YES||3.2||1037||tilting||no||4000||3.0||no||no|
|Sony A7R II (⇒ lft)||2400||no||3.0||1229||tilting||no||8000||5.0||no||YES|
|Canon 5DS R (⇒ lft | rgt)||optical||YES||3.2||1040||fixed||no||8000||5.0||no||no|
|Canon 5DS (⇒ lft | rgt)||optical||YES||3.2||1040||fixed||no||8000||5.0||no||no|
|Hasselblad X1D (⇒ lft | rgt)||2360||no||3.0||920||fixed||YES||2000||2.3||no||no|
|Leica SL (⇒ lft | rgt)||4400||YES||3.0||1040||fixed||YES||8000||11.0||no||no|
|Nikon D750 (⇒ lft | rgt)||optical||YES||3.2||1229||tilting||no||4000||6.0||12||no|
|Nikon D810 (⇒ lft | rgt)||optical||YES||3.2||1229||fixed||no||4000||5.0||12||no|
|Nikon D4S (⇒ lft | rgt)||optical||YES||3.2||921||fixed||no||8000||11.0||no||no|
|Pentax 645D (⇒ lft | rgt)||optical||YES||3.0||921||fixed||no||4000||1.1||no||no|
|Sony A7R III (⇒ lft | rgt)||3686||no||3.0||1440||tilting||YES||8000||10.0||no||YES|
|Sony A99 II (⇒ lft | rgt)||2400||YES||3.0||1229||tilting||no||8000||12.0||no||YES|
|Sony A7S II (⇒ lft | rgt)||2400||no||3.0||1229||tilting||no||8000||5.0||no||YES|
|Sony RX1R II (⇒ lft | rgt)||2360||no||3.0||1229||tilting||no||4000||5.0||no||no|
|Sony A7 II (⇒ lft | rgt)||2400||no||3.0||1230||tilting||no||8000||5.0||no||YES|
|Sony A7S (⇒ lft | rgt)||2400||no||3.0||921||tilting||no||8000||5.0||no||no|
|Sony A7R (⇒ lft | rgt)||2400||no||3.0||1230||tilting||no||8000||4.0||no||no|
The 645Z is a current model that online retailers, such as amazon, will have in stock. In contrast, the A7R II has been discontinued (but it can be found pre-owned on ebay). As a replacement in the same line of cameras, the A7R II was succeeded by the Sony Alpha A7R III.
So how do things add up? Is there a clear favorite between the Pentax 645Z and the Pentax 645Z? The listing below highlights the relative strengths of the two models.
Arguments in favor of the Pentax 645Z:
- More detail: Offers more megapixels (51.1 vs 42.2MP) with a 8% higher linear resolution.
- More dynamic range: Captures a larger spectrum of light and dark details (0.8 EV of extra DR).
- Better low-light sensitivity: Requires less light for good images (0.4 stops ISO advantage).
- Brighter framing: Features an optical viewfinder for clear, lag-free composition.
- Easier setting verification: Has an LCD display on top to control shooting parameters.
- Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
- Longer lasting: Can take more shots (650 versus 290) on a single battery charge.
- More heavily discounted: Has been on the market for longer (launched in April 2014).
Advantages of the Sony Alpha A7R II:
- Better video: Provides higher definition movie capture (4K/30p vs 1080/60i).
- More framing info: Has an electronic viewfinder that displays shooting data.
- More detailed LCD: Has a higher resolution rear screen (1229k vs 1037k dots).
- Faster shutter: Has higher mechanical shutter speed (8000/sec vs 4000/sec) to freeze action.
- Faster burst: Shoots at higher frequency (5 vs 3 flaps/sec) to capture the decisive moment.
- More compact: Is smaller (127x96mm vs 156x117mm) and will fit more readily into a bag.
- Less heavy: Has a lower weight (by 925g or 60 percent) and is thus easier to take along.
- More legacy lens friendly: Can use many non-native lenses via adapters.
- Sharper images: Has stabilization technology build-in to reduce the impact of hand-shake.
- More affordable: Was introduced into a lower priced category (62 percent cheaper at launch).
- More modern: Was introduced somewhat (1 year and 1 month) more recently.
If the number of relative strengths (bullet points above) is taken as a guide, the A7R II emerges as the winner of the match-up (11 : 8 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features.
In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it remains partial and cannot reveal, for example, the handling experience and imaging performance when actually working with the 645Z or the A7R II. User reviews that are available, for instance, at amazon can sometimes shed light on these issues, but such feedback is all too often partial, inconsistent, and inaccurate. This is why hands-on reviews by experts are important. The adjacent table relays the overall verdicts of several of the most popular camera review sites. The full reviews are available, respectively, at cameralabs.com, dpreview.com, ephotozine.com, imaging-resource.com, and photographyblog.com.
|Pentax 645Z (⇒ rgt)||-||-||4.5/5||5/5||5/5||2014||8,499||latest||check|
|Sony A7R II (⇒ lft)||HiRec||90/100 Gold||5/5||4.5/5||5/5||2015||3,199||discont.||check|
|Canon 5DS R (⇒ lft | rgt)||Rec||83/100 Silver||5/5||5/5||4.5/5||2015||3,699||latest||check|
|Canon 5DS (⇒ lft | rgt)||Rec||83/100 Silver||4.5/5||5/5||4.5/5||2015||3,699||latest||check|
|Hasselblad X1D (⇒ lft | rgt)||-||-||-||-||4/5||2016||8,995||latest||check|
|Leica SL (⇒ lft | rgt)||-||84/100||4.5/5||4/5||4/5||2015||7,450||latest||check|
|Nikon D750 (⇒ lft | rgt)||HiRec||90/100 Gold||4.5/5||5/5||4.5/5||2014||2,299||latest||check|
|Nikon D810 (⇒ lft | rgt)||-||86/100 Gold||5/5||4.5/5||4.5/5||2014||3,299||discont.||check|
|Nikon D4S (⇒ lft | rgt)||-||-||4.5/5||5/5||4.5/5||2014||6,499||discont.||check|
|Pentax 645D (⇒ lft | rgt)||-||-||-||4.5/5||-||2010||9,995||discont.||check|
|Sony A7R III (⇒ lft | rgt)||HiRec||90/100 Gold||4.5/5||5/5||5/5||2017||3,199||latest||check|
|Sony A99 II (⇒ lft | rgt)||-||85/100 Silver||4.5/5||4.5/5||4.5/5||2016||3,199||latest||check|
|Sony A7S II (⇒ lft | rgt)||Rec||-||4.5/5||5/5||5/5||2015||2,999||latest||check|
|Sony RX1R II (⇒ lft | rgt)||-||82/100 Silver||-||reviewed||4.5/5||2015||3,299||latest||check|
|Sony A7 II (⇒ lft | rgt)||Rec||82/100 Silver||4.5/5||5/5||5/5||2014||1,999||latest||check|
|Sony A7S (⇒ lft | rgt)||-||86/100 Gold||4.5/5||4.5/5||5/5||2014||2,499||discont.||check|
|Sony A7R (⇒ lft | rgt)||HiRec||82/100 Gold||4.5/5||5/5||5/5||2013||2,299||discont.||check|
The review scores listed above should be treated with care, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparisons of ratings among very different cameras or across long time periods have little meaning. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.
In case you would like to check on the differences and similarities of other camera models, just use the search menu below. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting. If you do not see the camera that you are looking for, please send me an email, and I will try to add information on that model to the database.
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