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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. Three consecutive perspectives from the front, the top, and the back are presented. 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
A7 II versus 645Z top view
A7 II and 645Z rear side
Body view (A7 II on the left)

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 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 camera comparisons there.

Camera Body Specifications
Camera Camera
Width
Camera
Height
Camera
Depth
Camera
Weight
Battery
Life
(CIPA)
Weather
Sealing
(y/n)
Camera
Launch
(year)
Launch
Price
(USD)
Street
Price
(amazon)
Used
Price
(ebay)
Sony A7 II (⇒ rgt) 127 mm 96 mm 60 mm 599 g 350 YES 2014 1,999discont. check
Pentax 645Z (⇒ lft) 156 mm 117 mm 123 mm 1550 g 650 YES 2014 8,499 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
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
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 800 YES 2010 9,995discont. check
Sony A7 III (⇒ lft | rgt) 127 mm 96 mm 74 mm 650 g 610 YES 2018 1,999 latest check
Sony A9 (⇒ lft | rgt) 127 mm 96 mm 63 mm 673 g 650 YES 2017 4,499 latest check
Sony A7R III (⇒ lft | rgt) 127 mm 96 mm 74 mm 650 g 650 YES 2017 3,199 latest check
Sony A7R II (⇒ lft | rgt) 127 mm 96 mm 60 mm 625 g 290 YES 2015 3,199discont. check
Sony A7S II (⇒ lft | rgt) 127 mm 96 mm 60 mm 627 g 370 YES 2015 2,999 latest check
Sony A77 II (⇒ lft | rgt) 143 mm 104 mm 81 mm 647 g 480 YES 2014 1,199 latest check
Sony A7 (⇒ lft | rgt) 127 mm 94 mm 48 mm 474 g 340 YES 2013 1,699discont. check
Sony A7R (⇒ lft | rgt) 127 mm 94 mm 48 mm 465 g 340 YES 2013 2,299discont. check
Sony A77 (⇒ lft | rgt) 143 mm 104 mm 81 mm 732 g 470 YES 2011 1,999discont. check

The price is, of course, an important factor in any camera decision. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The A7 II was launched at a markedly lower price (by 76 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.


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.

Sony A7 II and Pentax 645Z sensor measures
Sensor size

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
Sensor resolution

For most 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 Sensor
Class
Resolution
(Megapixel)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Sony A7 II (⇒ rgt) Full Frame 24.0 6000 4000 1080/60p 24.9 13.6 2449 90
Pentax 645Z (⇒ lft) Medium Format 51.1 8256 6192 1080/60i 26.0 14.7 4505 101
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
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
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 A7 III (⇒ lft | rgt) Full Frame 24.0 6000 4000 4K/30p 25.0 14.7 3730 96
Sony A9 (⇒ lft | rgt) Full Frame 24.0 6000 4000 4K/30p 24.9 13.3 3517 92
Sony A7R III (⇒ lft | rgt) Full Frame 42.2 7952 5304 4K/30p 26.0 14.7 3523 100
Sony A7R II (⇒ lft | rgt) Full Frame 42.2 7952 5304 4K/30p 26.0 13.9 3434 98
Sony A7S II (⇒ lft | rgt) Full Frame 12.0 4240 2832 4K/30p 23.6 13.3 2993 85
Sony A77 II (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p - - - -
Sony A7 (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 24.8 14.2 2248 90
Sony A7R (⇒ lft | rgt) Full Frame 36.2 7360 4912 1080/60p 25.6 14.1 2746 95
Sony A77 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p 24 13.2 801 78

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 Viewfinder
(Type or
'000 dots)
Control
Panel
(Y/n)
LCD
Size
(inch)
LCD
Resolution
('000 dots)
LCD
Attach-
ment
Touch
Screen
(Y/n)
Shutter
speed
(1/sec)
Shutter
flaps
(1/sec))
Build-in
Flash
(GN)
Build-in
Image
Stab
Sony A7 II (⇒ rgt) 2400 no 3.0 1230 tilting no 8000 5.0 no YES
Pentax 645Z (⇒ lft) optical YES 3.2 1037 tilting no 4000 3.0 no no
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
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
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 A7 III (⇒ lft | rgt) 2359 no 3.0 922 tilting YES 8000 10 no YES
Sony A9 (⇒ lft | rgt) 3686 no 3.0 1440 tilting YES 8000 20.0 no YES
Sony A7R III (⇒ lft | rgt) 3686 no 3.0 1440 tilting YES 8000 10.0 no YES
Sony A7R II (⇒ lft | rgt) 2400 no 3.0 1229 tilting no 8000 5.0 no YES
Sony A7S II (⇒ lft | rgt) 2400 no 3.0 1229 tilting no 8000 5.0 no YES
Sony A77 II (⇒ lft | rgt) 2359 YES 3.0 1229 full-flex no 8000 12.0 12 YES
Sony A7 (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 5.0 no no
Sony A7R (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 4.0 no no
Sony A77 (⇒ lft | rgt) 2359 YES 3.0 921 full-flex no 8000 12.0 12 YES

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. The detailed reviews can be accessed, respectively, on the websites of cameralabs.com, dpreview.com, ephotozine.com, imaging-resource.com, and photographyblog.com.

Review scores
Camera camera
labs
.com
dp
review
.com
ephoto
zine
.com
imaging
resource
.com
photography
blog
.com
Camera
Launch
(year)
Launch
Price
(USD)
Street
Price
(amazon)
Used
Price
(ebay)
Sony A7 II (⇒ rgt) Rec 82/100 Silver 4.5/5 5/5 5/5 2014 1,999discont. check
Pentax 645Z (⇒ lft) - - 4.5/5 5/5 5/5 2014 8,499 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
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
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 9,995discont. check
Sony A7 III (⇒ lft | rgt) HiRec 89/100 Gold 5/5 .. 5/5 2018 1,999 latest check
Sony A9 (⇒ lft | rgt) HiRec 89/100 Gold 5/5 5/5 5/5 2017 4,499 latest check
Sony A7R III (⇒ lft | rgt) HiRec 90/100 Gold 4.5/5 5/5 5/5 2017 3,199 latest check
Sony A7R II (⇒ lft | rgt) HiRec 90/100 Gold 5/5 4.5/5 5/5 2015 3,199discont. check
Sony A7S II (⇒ lft | rgt) Rec - 4.5/5 5/5 5/5 2015 2,999 latest check
Sony A77 II (⇒ lft | rgt) - 80/100 Silver 4.5/5 4/5 5/5 2014 1,199 latest check
Sony A7 (⇒ lft | rgt) HiRec 80/100 Silver 5/5 4.5/5 5/5 2013 1,699discont. check
Sony A7R (⇒ lft | rgt) HiRec 82/100 Gold 4.5/5 5/5 5/5 2013 2,299discont. check
Sony A77 (⇒ lft | rgt) 91/100 81/100 Silver - 4.5/5 5/5 2011 1,999discont. check

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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