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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 physical size and weight of the Sony A7 II and the Pentax 645Z are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear are shown. All size dimensions are rounded to the nearest millimeter. If you prefer, you can also use the toggle button to switch to a comparison in percentage 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 table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. In case you want to display and compare another camera duo, just click on the right or left arrow next to the camera that you would like to inspect. Alternatively, you can also use the CAM-parator to select your camera combination among a larger number of options.

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« » 6.0 in 4.6 in 3.0 in 32.8 oz 700 Y Feb 2015 3,699 i i Canon 5DS
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
Hasselblad X1D« » 5.9 in 3.9 in 2.8 in 25.6 oz .. Y Jun 2016 8,995 i i Hasselblad X1D
Leica SL« » 5.8 in 4.1 in 1.5 in 29.9 oz 400 Y Oct 2015 7,450 i i Leica SL
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
Panasonic GH5« » 5.5 in 3.9 in 3.4 in 25.6 oz 410 Y Jan 2017 1,999 i i Panasonic GH5
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 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 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 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 A7« » 5.0 in 3.7 in 1.9 in 16.7 oz 340 Y Oct 2013 1,699- i Sony A7
Sony A77« » 5.6 in 4.1 in 3.2 in 25.8 oz 470 Y Aug 2011 1,999- i Sony A77
Sony A850« » 6.1 in 4.6 in 3.2 in 31.6 oz 880 Y Aug 2009 1,999- i Sony A850

The price is, of course, an important factor in any camera decision. The retail prices at the time of the camera’s release place the model in the market relative to other models in the producer’s line-up and the competition. 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. A large sensor will generally have larger individual pixels that offer better low-light sensitivity, provide wider dynamic range, and have richer color-depth than smaller pixels in a sensor of the same technological generation. Further, a large sensor camera will give the photographer additional creative options when using shallow depth-of-field to isolate a subject from its background. On the downside, larger sensors tend to be more expensive and 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

Consistent information on actual sensor performance is available from DXO Mark for many 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"). 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 following table provides an overview of the physical sensor characteristics, as well as the sensor quality measurements for a selection of comparators.

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« » Full Frame 50.3 8688 57921080/60p24.712.4238187Canon 5DS
Canon 5DS R« » Full Frame 50.3 8688 57921080/60p24.612.4230886Canon 5DS R
Hasselblad X1D« » Medium Format 51.3 8272 62001080/25p26.214.84489102Hasselblad X1D
Leica SL« » Full Frame 24.0 6000 40004K/30p25.013.4182188Leica SL
Olympus E-M1 II« » Four Thirds 20.2 5184 38884K/30p23.712.8131280Olympus E-M1 II
Panasonic GH5« » Four Thirds 20.2 5184 38884K/60p23.913.080777Panasonic GH5
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 A7R III« » Full Frame 42.2 7952 53044K/30p26.014.73523100Sony A7R III
Sony A9« » Full Frame 24.0 6000 40004K/30p24.913.3351792Sony A9
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 A7« » Full Frame 24.0 6000 40001080/60p24.814.2224890Sony A7
Sony A77« » APS-C 24.0 6000 40001080/60p24.013.280178Sony A77
Sony A850« » Full Frame 24.4 6048 4032-23.812.2141579Sony A850

Many modern cameras cannot only take still pictures, but also record videos. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, 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

Beyond 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 table below summarizes some of the other core capabilities of the Sony A7 II and Pentax 645Z in connection with corresponding information for a sample of similar 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« »optical Y 3.2 1040 fixed n 8000 5.0 n n Canon 5DS
Canon 5DS R« »optical Y 3.2 1040 fixed n 8000 5.0 n n Canon 5DS R
Hasselblad X1D« »2360 n 3.0 920 fixed Y 2000 2.3 n n Hasselblad X1D
Leica SL« »4400 Y 3.0 1040 fixed Y 8000 11.0 n n Leica SL
Olympus E-M1 II« »2360 n 3.0 1037 swivel Y 8000 18.0 n Y Olympus E-M1 II
Panasonic GH5« »3680 n 3.2 1620 swivel Y 8000 12.0 n Y Panasonic GH5
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 A7R III« »3686 n 3.0 1440 tilting Y 8000 10.0 n Y Sony A7R III
Sony A9« »3686 n 3.0 1440 tilting Y 8000 20.0 n Y Sony A9
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 A7« »2400 n 3.0 1230 tilting n 8000 5.0 n n Sony A7
Sony A77« »2359 Y 3.0 921 full-flex n 8000 12.0 Y Y Sony A77
Sony A850« »optical Y 3.0 922 fixed n 8000 3.0 n Y Sony A850

One feature that differentiates the A7 II and the 645Z is in-body image stabilization (IBIS). The A7 II reduces the risk of handshake-induced blur with all attached lenses, while the 645Z has to rely on optical image stabilization in OIS-equipped lenses to achieve the same effect.

The A7 II writes its imaging data to SDXC or Memory Stick PRO Duo cards, while the 645Z uses SDXC cards. The 645Z features dual card slots, which can be very useful in case a memory card fails. In contrast, the A7 II only has one slot.

Input-Output Connections
  Camera
Model
Hotshoe
Port
Internal
Microphone
Internal
Speaker
Microphone
Port
Headphone
Port
HDMI
Port
USB
Type
WiFi
Support
NFC
Support
Bluetooth
Support
Camera
Model
Sony A7 II»YstereomonoYYmicro2.0YY-Sony A7 II
Pentax 645Z«YstereomonoY-mini3.0---Pentax 645Z
Canon 5DS« »YmonomonoY-mini3.0---Canon 5DS
Canon 5DS R« »YmonomonoY-mini3.0---Canon 5DS R
Hasselblad X1D« »YstereomonoYYmini3.0Y--Hasselblad X1D
Leica SL« »YstereomonoYYfull3.0Y--Leica SL
Olympus E-M1 II« »YstereomonoYYmicro3.0Y--Olympus E-M1 II
Panasonic GH5« »YstereomonoYYfull3.1Y-YPanasonic GH5
Pentax 645D« »Ystereo----2.0---Pentax 645D
Sony A7 III« »YstereomonoYYmicro3.1YYYSony A7 III
Sony A7R III« »YstereomonoYYmicro3.1YYYSony A7R III
Sony A9« »YstereomonoYYmicro2.0YYYSony A9
Sony A7R II« »YstereomonoYYmicro2.0YY-Sony A7R II
Sony A7S II« »YstereomonoYYmicro2.0YY-Sony A7S II
Sony A7« »YstereomonoYYmicro2.0YY-Sony A7
Sony A77« »YstereomonoY-mini2.0---Sony A77
Sony A850« »Y----mini2.0---Sony A850

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 is the bottom line? Is there a clear favorite between the Sony A7 II and the Pentax 645Z? A synthesis of the relative strong points of each of the models is listed below.

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Advantages 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).
  • Better sound control: Has a headphone port that enables audio monitoring while recording.
  • 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.
  • Sharper images: Has hand-shake reducing image stabilization build-in.
  • More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
  • Easier file upload: Has wifi build in for automatic backup or image transfer to the web.
  • Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
  • 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: Features 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.
  • Faster data transfer: Supports a more advanced USB protocol (3.0 vs 2.0).
  • Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
  • More heavily discounted: Has been on the market for longer (launched in April 2014).

If the number of relative strengths (bullet points above) is taken as a guide, the A7 II emerges as the winner of the contest (15 : 13 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 15:13 645Z

In any case, while the specs-based evaluation of cameras is instructive in revealing their potential as photographic tools, it remains partial and cannot reveal, for example, the handling experience and imaging performance when actually working with the A7 II or the 645Z. At times, user reviews, such as those published at amazon, address these issues in a useful manner, but such feedback is on many occasions incomplete, inconsistent, and unreliable. This is why hands-on reviews by experts are important. The table below summarizes the assessments of some of the best known 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« »Rec83/1004.5/55/54.5/5 Feb 2015 3,699 i i Canon 5DS
Canon 5DS R« »Rec83/1005/55/54.5/5 Feb 2015 3,699 i i Canon 5DS R
Hasselblad X1D« »rev81/100--4/5 Jun 2016 8,995 i i Hasselblad X1D
Leica SL« »-84/1004.5/54/54/5 Oct 2015 7,450 i i Leica SL
Olympus E-M1 II« »HiRec85/1004.5/55/54.5/5 Sep 2016 1,999 i i Olympus E-M1 II
Panasonic GH5« »HiRec85/1004.5/55/55/5 Jan 2017 1,999 i i Panasonic GH5
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 A7R III« »HiRec90/1004.5/55/55/5 Oct 2017 3,199 i i Sony A7R III
Sony A9« »HiRec89/1005/55/55/5 Apr 2017 4,499 i i Sony A9
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 A7« »HiRec80/1005/54.5/55/5 Oct 2013 1,699- i Sony A7
Sony A77« »91/10081/100-4.5/55/5 Aug 2011 1,999- i Sony A77
Sony A850« »-75/100-4/54.5/5 Aug 2009 1,999- i Sony A850

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. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, 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.

 

Other camera comparisons

Did this review help to inform your camera decision process? If you would like to see a different side-by-side camera review, just make a corresponding selection in the search boxes 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 you cannot find the camera you are interested in, kindly get in touch, and I will try to update the database with the necessary infos.

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