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Sony A7 II versus Pentax 645Z

The Sony Alpha A7 II and the Pentax 645Z are two digital cameras that were officially introduced, respectively, in November 2014 and April 2014. The A7 II is a mirrorless interchangeable lens camera, while the 645Z is a DSLR. The cameras are based on a full frame (A7 II) and a medium format (645Z) sensor. The Sony has a resolution of 24 megapixel, whereas the Pentax provides 51.1 MP. Read on to find out how these two cameras compare with respect to their size, their sensors, their features, and their reception by expert reviewers.

Body comparison: Sony A7 II vs Pentax 645Z

The side-by-side display below illustrates the physical size and weight of the Sony A7 II and the Pentax 645Z. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All width, height and depth measures 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 A7 II – represents the basis for the calculations across all the size and weight measures).

Compare Sony A7 II vs Pentax 645Z
Compare A7 II versus 645Z top
Compare A7 II and 645Z rear

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax 645Z is considerably larger (50 percent) than the Sony A7 II. Moreover, the 645Z is substantially heavier (159 percent) than the A7 II. 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.

Concerning battery life, the A7 II gets 350 shots out of its NP-FW50 battery, while the 645Z can take 650 images on a single charge of its D-LI90 power pack.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. If you would like to visualize and compare a different camera combination, just use the right or left arrows in the table to switch to the respective camera. Alternatively, you can also navigate to the CAM-parator app and make your selection from the full list of cameras there.

Camera Body Specifications
  Camera
Model
Camera
Width
Camera
Height
Camera
Depth
Camera
Weight
Battery
Life
(CIPA)
Weather
Sealing
(yes/no)
Camera
Launch
(announced)
Launch
Price
(USD)
Street
Price
(USD)
Used
Price
(USD)
Camera
Model
Sony A7 II» 5.0 in 3.8 in 2.4 in 21.1 oz 350 Y Nov 2014 1,999- i Sony A7 II
Pentax 645Z« 6.1 in 4.6 in 4.8 in 54.7 oz 650 Y Apr 2014 8,499 i i Pentax 645Z
Canon 5DS R« » 6.0 in 4.6 in 3.0 in 32.8 oz 700 Y Feb 2015 3,699 i i Canon 5DS R
Canon 5DS« » 6.0 in 4.6 in 3.0 in 32.8 oz 700 Y Feb 2015 3,699 i i Canon 5DS
Leica SL« » 5.8 in 4.1 in 1.5 in 29.9 oz 400 Y Oct 2015 7,450 i i Leica SL
Nikon D750« » 5.6 in 4.4 in 3.1 in 26.5 oz 1230 Y Sep 2014 2,299 i i Nikon D750
Olympus E-M1 II« » 5.3 in 3.6 in 2.6 in 20.2 oz 440 Y Sep 2016 1,999 i i Olympus E-M1 II
Pentax 645D« » 6.1 in 4.6 in 4.7 in 52.2 oz 800 Y Mar 2010 9,995- i Pentax 645D
Sony A7 III« » 5.0 in 3.8 in 2.9 in 22.9 oz 610 Y Feb 2018 1,999 i i Sony A7 III
Sony A9« » 5.0 in 3.8 in 2.5 in 23.7 oz 650 Y Apr 2017 4,499 i i Sony A9
Sony A7R III« » 5.0 in 3.8 in 2.9 in 22.9 oz 650 Y Oct 2017 3,199 i i Sony A7R III
Sony A7R II« » 5.0 in 3.8 in 2.4 in 22.0 oz 290 Y Jun 2015 3,199- i Sony A7R II
Sony A7S II« » 5.0 in 3.8 in 2.4 in 22.1 oz 370 Y Sep 2015 2,999 i i Sony A7S II
Sony A77 II« » 5.6 in 4.1 in 3.2 in 22.8 oz 480 Y May 2014 1,199 i i Sony A77 II
Sony A7« » 5.0 in 3.7 in 1.9 in 16.7 oz 340 Y Oct 2013 1,699- i Sony A7
Sony A7R« » 5.0 in 3.7 in 1.9 in 16.4 oz 340 Y Oct 2013 2,299- i Sony A7R
Sony A77« » 5.6 in 4.1 in 3.2 in 25.8 oz 470 Y Aug 2011 1,999- i Sony A77

The camera’s price is obviously a critical decision-making factor. The manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The A7 II was launched at a markedly lower price (by 76 percent) than the 645Z, which puts it into a different market segment. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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.

 

Sensor comparison: Sony A7 II vs Pentax 645Z

The size of the sensor inside a digital camera is one of the key determinants 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 tend to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Sony A7 II features a full frame sensor and the Pentax 645Z a medium format sensor. The sensor area in the 645Z is 68 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 0.79. The sensor in the A7 II has a native 3:2 aspect ratio, while the one in the 645Z offers a 4:3 aspect.

Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) sensors.

Sony A7 II and Pentax 645Z sensor measures

With 51.1MP, the 645Z offers a higher resolution than the A7 II (24MP), but the 645Z has smaller individual pixels (pixel pitch of 5.30μm versus 5.97μm for the A7 II). It is noteworthy in this context that the A7 II is a somewhat more recent model (by 7 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 pixel-units. 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.

A7 II versus 645Z MP

For many cameras, data on sensor performance has been reported by DXO Mark. 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"). Of the two cameras under consideration, the 645Z offers substantially better image quality than the A7 II (overall score 11 points higher). The advantage is based on 1.1 bits higher color depth, 1.1 EV in additional dynamic range, and 0.9 stops in additional low light sensitivity. The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.

Sensor Characteristics
  Camera
Model
Sensor
Class
Resolution
(MP)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Camera
Model
Sony A7 II» Full Frame 24.0 6000 40001080/60p24.913.6244990Sony A7 II
Pentax 645Z« Medium Format 51.1 8256 61921080/60i26.014.74505101Pentax 645Z
Canon 5DS R« » Full Frame 50.3 8688 57921080/60p24.612.4230886Canon 5DS R
Canon 5DS« » Full Frame 50.3 8688 57921080/60p24.712.4238187Canon 5DS
Leica SL« » Full Frame 24.0 6000 40004K/30p25.013.4182188Leica SL
Nikon D750« » Full Frame 24.2 6016 40161080/60p24.814.5295693Nikon D750
Olympus E-M1 II« » Four Thirds 20.2 5184 38884K/30p23.712.8131280Olympus E-M1 II
Pentax 645D« » Medium Format 39.5 7264 5440-24.612.6126282Pentax 645D
Sony A7 III« » Full Frame 24.0 6000 40004K/30p25.014.7373096Sony A7 III
Sony A9« » Full Frame 24.0 6000 40004K/30p24.913.3351792Sony A9
Sony A7R III« » Full Frame 42.2 7952 53044K/30p26.014.73523100Sony A7R III
Sony A7R II« » Full Frame 42.2 7952 53044K/30p26.013.9343498Sony A7R II
Sony A7S II« » Full Frame 12.0 4240 28324K/30p23.613.3299385Sony A7S II
Sony A77 II« » APS-C 24.0 6000 40001080/60p----Sony A77 II
Sony A7« » Full Frame 24.0 6000 40001080/60p24.814.2224890Sony A7
Sony A7R« » Full Frame 36.2 7360 49121080/60p25.614.1274695Sony A7R
Sony A77« » APS-C 24.0 6000 40001080/60p24.013.280178Sony A77

Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the A7 II provides a higher frame rate than the 645Z. It can shoot video footage at 1080/60p, while the Pentax is limited to 1080/60i.

 

Feature comparison: Sony A7 II vs Pentax 645Z

Apart from body and sensor, cameras can and do differ across a range of features. For example, the A7 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 following table reports on some other key feature differences and similarities of the Sony A7 II, the Pentax 645Z, and comparable cameras. If needed, the dpreview camera hub, for example, contains further detail on the cameras' specs.

Core Features
  Camera
Model
Viewfinder
(Type or
'000 dots)
Control
Panel
(yes/no)
LCD
Size
(inch)
LCD
Resolution
('000 dots)
LCD
Attach-
ment
Touch
Screen
(yes/no)
Shutter
speed
(1/sec)
Shutter
flaps
(1/sec))
Build-in
Flash
(yes/no)
Build-in
Image
Stab
Camera
Model
Sony A7 II»2400 n 3.0 1230 tilting n 8000 5.0 n Y Sony A7 II
Pentax 645Z«optical Y 3.2 1037 tilting n 4000 3.0 n n Pentax 645Z
Canon 5DS R« »optical Y 3.2 1040 fixed n 8000 5.0 n n Canon 5DS R
Canon 5DS« »optical Y 3.2 1040 fixed n 8000 5.0 n n Canon 5DS
Leica SL« »4400 Y 3.0 1040 fixed Y 8000 11.0 n n Leica SL
Nikon D750« »optical Y 3.2 1229 tilting n 4000 6.0 Y n Nikon D750
Olympus E-M1 II« »2360 n 3.0 1037 swivel Y 8000 18.0 n Y Olympus E-M1 II
Pentax 645D« »optical Y 3.0 921 fixed n 4000 1.1 n n Pentax 645D
Sony A7 III« »2359 n 3.0 922 tilting Y 8000 10.0 n Y Sony A7 III
Sony A9« »3686 n 3.0 1440 tilting Y 8000 20.0 n Y Sony A9
Sony A7R III« »3686 n 3.0 1440 tilting Y 8000 10.0 n Y Sony A7R III
Sony A7R II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7R II
Sony A7S II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7S II
Sony A77 II« »2359 Y 3.0 1229 full-flex n 8000 12.0 Y Y Sony A77 II
Sony A7« »2400 n 3.0 1230 tilting n 8000 5.0 n n Sony A7
Sony A7R« »2400 n 3.0 1230 tilting n 8000 4.0 n n Sony A7R
Sony A77« »2359 Y 3.0 921 full-flex n 8000 12.0 Y Y Sony A77

The 645Z is a current model that online retailers, such as amazon, will have in stock. In contrast, the A7 II has been discontinued (but it can be found pre-owned on eBay). As a replacement in the same line of cameras, the A7 II was succeeded by the Sony A7 III.

Review summary: Sony A7 II vs Pentax 645Z

So what conclusions can be drawn? Is there a clear favorite between the Sony A7 II and the Pentax 645Z? The listing below highlights the relative strengths of the two models.

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Arguments in favor of the Sony Alpha A7 II:

  • Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
  • Better video: Provides higher movie framerates (1080/60p versus 1080/60i).
  • More framing info: Has an electronic viewfinder that displays shooting data.
  • More detailed LCD: Has a higher resolution rear screen (1230k 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 thus needs less room in the bag.
  • Less heavy: Is lighter (by 951g or 61 percent) and hence easier to carry around.
  • More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
  • Sharper images: Has hand-shake reducing image stabilization build-in.
  • More affordable: Was introduced into a lower priced category (76 percent cheaper at launch).
  • More modern: Is somewhat more recent (announced 7 months after the 645Z).

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Reasons to prefer the Pentax 645Z:

  • More detail: Has more megapixels (51.1 vs 24MP), which boosts linear resolution by 43%.
  • Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
  • Better image quality: Scores substantially higher (11 points) in the DXO overall evaluation.
  • Richer colors: Generates noticeably more natural colors (1.1 bits more color depth).
  • More dynamic range: Captures a broader range of light and dark details (1.1 EV of extra DR).
  • Better low-light sensitivity: Can shoot in dim conditions (0.9 stops ISO advantage).
  • Brighter framing: Features an optical viewfinder for clear, lag-free composition.
  • Easier setting verification: Has a control panel on top to check shooting parameters.
  • Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
  • Longer lasting: Gets more shots (650 versus 350) out of a single battery charge.
  • More heavily discounted: Has been on the market for longer (launched in April 2014).

If the count of relative strengths (bullet points above) is taken as a measure, the A7 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 when reflecting and deciding on a new camera.

A7 II 12:11 645Z

In any case, while the specs-based evaluation of cameras is instructive in revealing their potential as photographic tools, it says nothing about, for example, the handling, responsiveness, and overall imaging quality of the A7 II and the 645Z in practical situations. 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 (cameralabs, dpreview, ephotozine, imaging-resource, photographyblog). The detailed reviews can be accessed by clicking on the site logo in the table header.

Review Scores
  Camera
Model
cameralabs dpreview ephotozine imaging-resource photographyblog Camera
Launch
(announced)
Launch
Price
(USD)
Street
Price
(USD)
Used
Price
(USD)
Camera
Model
Sony A7 II»Rec82/1004.5/55/55/5 Nov 2014 1,999- i Sony A7 II
Pentax 645Z«--4.5/55/55/5 Apr 2014 8,499 i i Pentax 645Z
Canon 5DS R« »Rec83/1005/55/54.5/5 Feb 2015 3,699 i i Canon 5DS R
Canon 5DS« »Rec83/1004.5/55/54.5/5 Feb 2015 3,699 i i Canon 5DS
Leica SL« »-84/1004.5/54/54/5 Oct 2015 7,450 i i Leica SL
Nikon D750« »HiRec90/1004.5/55/54.5/5 Sep 2014 2,299 i i Nikon D750
Olympus E-M1 II« »HiRec85/1004.5/55/54.5/5 Sep 2016 1,999 i i Olympus E-M1 II
Pentax 645D« »---4.5/5- Mar 2010 9,995- i Pentax 645D
Sony A7 III« »HiRec89/1005/55/55/5 Feb 2018 1,999 i i Sony A7 III
Sony A9« »HiRec89/1005/55/55/5 Apr 2017 4,499 i i Sony A9
Sony A7R III« »HiRec90/1004.5/55/55/5 Oct 2017 3,199 i i Sony A7R III
Sony A7R II« »HiRec90/1005/54.5/55/5 Jun 2015 3,199- i Sony A7R II
Sony A7S II« »Rec-4.5/55/55/5 Sep 2015 2,999 i i Sony A7S II
Sony A77 II« »-80/1004.5/54/55/5 May 2014 1,199 i i Sony A77 II
Sony A7« »HiRec80/1005/54.5/55/5 Oct 2013 1,699- i Sony A7
Sony A7R« »HiRec82/1004.5/55/55/5 Oct 2013 2,299- i Sony A7R
Sony A77« »91/10081/100-4.5/55/5 Aug 2011 1,999- i Sony A77

Care should be taken when interpreting the review scores above, though. The assessments were made in relation to similar cameras of the same technological generation. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

 

Other camera comparisons

Did this review help to inform your camera decision process? In case you would like to check on the differences and similarities of other camera models, just use the search menu below. An an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool. If the camera you are interested in is not available, kindly get in touch, and I will try to locate and add the respective data to the application.

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