Pentax 645Z versus Sony A7S II
The Pentax 645Z and the Sony Alpha 7S II are two professional cameras that were announced, respectively, in April 2014 and September 2015. The 645Z is a DSLR, while the A7S 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 12 MP.
The physical size and weight of the Pentax 645Z and the Sony A7S II are illustrated 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 – the 645Z – represents 100 percent 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 A7S II is notably smaller (33 percent) than the Pentax 645Z. Moreover, the A7S 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 A7S II (⇒ lft)||127 mm||96 mm||60 mm||627 g||370||YES||2015||2,999||latest||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|
|Olympus E-M1 II (⇒ lft | rgt)||134 mm||91 mm||67 mm||574 g||440||YES||2016||1,999||latest||check|
|Pentax 645D (⇒ lft | rgt)||156 mm||117 mm||119 mm||1480 g||..||YES||2010||9,995||discont.||check|
|Sony A99 II (⇒ lft | rgt)||143 mm||104 mm||76 mm||849 g||490||YES||2016||3,199||latest||check|
|Sony A7R II (⇒ lft | rgt)||127 mm||96 mm||60 mm||625 g||290||YES||2015||3,199||discont.||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|
The listed prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The A7S II was launched at a markedly lower price (by 65 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 imaging sensor is at the core of digital cameras and its size is one of the main determining factors of image quality. A large sensor will tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color depth than smaller pixel-units 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 A7S II a full frame sensor. The sensor area in the A7S II is 41 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 A7S II offers a 3:2 aspect.
With 51.1MP, the 645Z offers a higher resolution than the A7S II (12MP), but the 645Z has smaller individual pixels (pixel pitch of 5.30μm versus 8.40μm for the A7S II). Moreover, the A7S II is a somewhat more recent model (by 1 year and 4 months) than the 645Z, and its sensor might have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixels. Coming back to sensor resolution, it should be mentioned that the 645Z has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.
For most cameras, data on sensor performance has been reported by DXO Mark. This service determines an overall sensor rating, as well as sub-scores for low-light sensitivity ("DXO Sports"), dynamic range ("DXO Landscape"), and color depth ("DXO Portrait"). Of the two cameras under review, the 645Z provides substantially higher image quality than the A7S II, with an overall score that is 16 points higher. This advantage is based on 2.4 bits higher color depth, 1.4 EV in additional dynamic range, and 0.6 stops in additional low light sensitivity. The table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar cameras.
|Pentax 645Z (⇒ rgt)||Medium Format||51.1||8256||6192||1080/60i||26.0||14.7||4505||101|
|Sony A7S II (⇒ lft)||Full Frame||12.0||4240||2832||4K/30p||23.6||13.3||2993||85|
|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|
|Olympus E-M1 II (⇒ lft | rgt)||Four Thirds||20.2||5184||3888||4K/30p||23.7||12.8||1312||80|
|Pentax 645D (⇒ lft | rgt)||Medium Format||39.5||7264||5440||no||24.6||12.6||1262||82|
|Sony A99 II (⇒ lft | rgt)||Full Frame||42.2||7952||5304||4K/30p||25.4||13.4||2317||92|
|Sony A7R II (⇒ lft | rgt)||Full Frame||42.2||7952||5304||4K/30p||26.0||13.9||3434||98|
|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|
Many modern cameras are not only capable of taking still images, but can also record movies. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the A7S 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 A7S 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 A7S 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 A7S 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|
|Olympus E-M1 II (⇒ lft | rgt)||2360||no||3.0||1037||swivel||YES||8000||18.0||no||YES|
|Pentax 645D (⇒ lft | rgt)||optical||YES||3.0||921||fixed||no||4000||1.1||no||no|
|Sony A99 II (⇒ lft | rgt)||2400||YES||3.0||1229||tilting||no||8000||12.0||no||YES|
|Sony A7R 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|
Both the 645Z and the A7S II are current models that good online retailers will have in stock. You can check the latest prices, for example, at amazon. The 645Z replaced the earlier Pentax 645D, while the A7S II followed on from the Sony A7S.
So what is the bottom line? Which of the two cameras – the Pentax 645Z or the Sony A7S II – has the upper hand? 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 12MP) with a 102% higher linear resolution.
- Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
- Better image quality: Scores substantially higher (16 points) in the DXO overall assessment.
- Richer colors: Generates images with noticeably better colors (2.4 bits more color depth).
- More dynamic range: Captures a larger spectrum of light and dark details (1.4 EV of extra DR).
- Better low-light sensitivity: Requires less light for good images (0.6 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 370) on a single battery charge.
- More heavily discounted: Has been on the market for longer (launched in April 2014).
Advantages of the Sony Alpha 7S II:
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- 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 923g 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 (65 percent cheaper at launch).
- More modern: Was introduced somewhat (1 year and 4 months) more recently.
If the number of relative strengths (bullet points above) is taken as a guide, the A7S II comes out slightly ahead of the 645Z (12 : 11 points). However, the relevance of individual strengths will vary across photographers, so that you might want to apply your own weighing scheme to the summary points.
In any case, while the specs-based evaluation of cameras is instructive in revealing their potential as photographic tools, it remains incomplete and does no justice, for example, to the way the 645Z or the A7S II handle or perform in practice. User reviews, such as those found at amazon, can sometimes inform about these issues, but such feedback is often incomplete, inconsistent, and biased. This is where reviews by experts come in. The following table reports the overall rankings of the cameras as published by some of the major camera review sites. The detailed reviews can be accessed, respectively, on the websites of 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 A7S II (⇒ lft)||Rec||-||4.5/5||5/5||5/5||2015||2,999||latest||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|
|Olympus E-M1 II (⇒ lft | rgt)||HiRec||85/100 Gold||4.5/5||5/5||4.5/5||2016||1,999||latest||check|
|Pentax 645D (⇒ lft | rgt)||-||-||-||4.5/5||-||2010||9,995||discont.||check|
|Sony A99 II (⇒ lft | rgt)||-||85/100 Silver||4.5/5||4.5/5||4.5/5||2016||3,199||latest||check|
|Sony A7R II (⇒ lft | rgt)||HiRec||90/100 Gold||5/5||4.5/5||5/5||2015||3,199||discont.||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|
Care should be taken when interpreting the review scores above, though. The ratings are only valid when refering to cameras in the same category and of the same age. 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 make your choice using the following search menu. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored. If the camera you are interested in is not available, kindly get in touch, and I will try to update the database with the necessary infos.
- Canon 1D Mark III vs Nikon D2Xs
- Canon 200D vs Fujifilm X-T20
- Canon 200D vs Pentax K-3 II
- Canon 550D vs Canon 700D
- Contax N Digital vs Canon 10D
- Fujifilm X-E2S vs Sony A7R
- Olympus E-620 vs Olympus E-450
- Olympus E-M10 III vs Olympus E-M5
- Panasonic GH5 vs Nikon D7200
- Panasonic GM5 vs Sony A6300
- Sony RX10 IV vs Nikon D7500
- Sony RX10 IV vs Sony RX1R II