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Pentax 645D versus Sony A7R

The Pentax 645D and the Sony Alpha A7R are two digital cameras that were officially introduced, respectively, in March 2010 and October 2013. The 645D is a DSLR, while the A7R is a mirrorless interchangeable lens camera. The cameras are based on a medium format (645D) and a full frame (A7R) sensor. The Pentax has a resolution of 39.5 megapixel, whereas the Sony provides 36.2 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: Pentax 645D vs Sony A7R

The physical size and weight of the Pentax 645D and the Sony A7R are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive views from the front, the top, and the rear side 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 – the 645D – represents the basis or 100 percent across all the size and weight measures).

Compare Pentax 645D vs Sony A7R
Compare 645D versus A7R top
Compare 645D and A7R rear

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7R is considerably smaller (35 percent) than the Pentax 645D. Moreover, the A7R is substantially lighter (69 percent) than the 645D. 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 645D gets 800 shots out of its D-LI90 battery, while the A7R can take 340 images on a single charge of its NP-FW50 power pack.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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
Pentax 645D» 6.1 in 4.6 in 4.7 in 52.2 oz 800 Y Mar 2010 9,995- i Pentax 645D
Sony A7R« 5.0 in 3.7 in 1.9 in 16.4 oz 340 Y Oct 2013 2,299- i Sony A7R
Canon 1D X Mark II« » 6.2 in 6.6 in 3.3 in 54.0 oz 1210 Y Feb 2016 5,999 i i Canon 1D X Mark II
Canon 1D X« » 6.2 in 6.6 in 3.3 in 54.7 oz 1120 Y Oct 2011 6,799- i Canon 1D X
Canon 1D Mark IV« » 6.1 in 6.2 in 3.1 in 43.4 oz 1500 Y Oct 2009 4,999- i Canon 1D Mark IV
Leica S Typ 006« » 6.3 in 4.7 in 3.1 in 44.4 oz .. Y Sep 2012 21,950- i Leica S Typ 006
Nikon D850« » 5.7 in 4.9 in 3.1 in 35.5 oz 1840 Y Jul 2017 3,299 i i Nikon D850
Nikon D5« » 6.3 in 6.3 in 3.6 in 49.9 oz 3780 Y Jan 2016 6,499 i i Nikon D5
Nikon D810« » 5.7 in 4.8 in 3.2 in 34.6 oz 1200 Y Jun 2014 3,299- i Nikon D810
Nikon D3S« » 6.3 in 6.2 in 3.5 in 43.7 oz 4200 Y Oct 2009 5,199- i Nikon D3S
Pentax 645Z« » 6.1 in 4.6 in 4.8 in 54.7 oz 650 Y Apr 2014 8,499 i i Pentax 645Z
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 A7 II« » 5.0 in 3.8 in 2.4 in 21.1 oz 350 Y Nov 2014 1,999- i Sony A7 II
Sony A7S« » 5.0 in 3.7 in 1.9 in 17.2 oz 380 Y Apr 2014 2,499- i Sony A7S
Sony A7« » 5.0 in 3.7 in 1.9 in 16.7 oz 340 Y Oct 2013 1,699- i Sony A7

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 A7R was launched at a markedly lower price (by 77 percent) than the 645D, 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.

 

Sensor comparison: Pentax 645D vs Sony A7R

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 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 associated with larger, more expensive camera bodies and lenses.

Of the two cameras under consideration, the Pentax 645D features a medium format sensor and the Sony A7R a full frame sensor. The sensor area in the A7R 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 645D has a native 4:3 aspect ratio, while the one in the A7R offers a 3:2 aspect.

Pentax 645D and Sony A7R sensor measures

With 39.5MP, the 645D offers a slightly higher resolution than the A7R (36.2MP), but the 645D nevertheless has larger individual pixels (pixel pitch of 6.06μm versus 4.88μm for the A7R) due to its larger sensor. However, the A7R is a somewhat more recent model (by 3 years and 7 months) than the 645D, 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 neither of the two cameras has an anti-alias filter installed, so they are able to capture all the detail the sensor resolves.

645D versus A7R MP

Consistent information on actual sensor performance is available from DXO Mark for many cameras. This service assesses and scores the color depth ("DXO Portrait"), dynamic range ("DXO Landscape"), and low-light sensitivity ("DXO Sports") of camera sensors, and also publishes an overall camera score. Of the two cameras under consideration, the A7R offers substantially better image quality than the 645D (overall score 13 points higher). The advantage is based on 1 bits higher color depth, 1.5 EV in additional dynamic range, and 1.1 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
Pentax 645D» Medium Format 39.5 7264 5440-24.612.6126282Pentax 645D
Sony A7R« Full Frame 36.2 7360 49121080/60p25.614.1274695Sony A7R
Canon 1D X Mark II« » Full Frame 20.0 5472 36484K/60p24.113.5320788Canon 1D X Mark II
Canon 1D X« » Full Frame 17.9 5184 34561080/30p23.811.8278682Canon 1D X
Canon 1D Mark IV« » APS-H 16.0 4896 32641080/30p22.812.0132074Canon 1D Mark IV
Leica S Typ 006« » Medium Format 37.5 7500 5000-23.912.282476Leica S Typ 006
Nikon D850« » Full Frame 45.4 8256 55044K/30p26.414.82660100Nikon D850
Nikon D5« » Full Frame 20.7 5588 37124K/30p25.112.3234388Nikon D5
Nikon D810« » Full Frame 36.2 7360 49121080/60p25.714.8285397Nikon D810
Nikon D3S« » Full Frame 12.1 4256 2832720/24p23.512.0325382Nikon D3S
Pentax 645Z« » Medium Format 51.1 8256 61921080/60i26.014.74505101Pentax 645Z
Sony A7R II« » Full Frame 42.2 7952 53044K/30p26.013.9343498Sony A7R II
Sony A7 II« » Full Frame 24.0 6000 40001080/60p24.913.6244990Sony A7 II
Sony A7S« » Full Frame 12.0 4240 28321080/60p23.913.2370287Sony A7S
Sony A7« » Full Frame 24.0 6000 40001080/60p24.814.2224890Sony A7

Many modern cameras are not only capable of taking still images, but can also record movies. The A7R indeed provides for movie recording, while the 645D does not. The highest resolution format that the A7R can use is 1080/60p.

 

Feature comparison: Pentax 645D vs Sony A7R

Beyond body and sensor, cameras can and do differ across a range of features. For example, the A7R has an electronic viewfinder (2400k dots), while the 645D 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 645D and Sony A7R along with similar information for a selection of comparators. If you need more detail on the specs, you can find comprehensive listings, for example, in the dpreview camera hub.

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
Pentax 645D»optical Y 3.0 921 fixed n 4000 1.1 n n Pentax 645D
Sony A7R«2400 n 3.0 1230 tilting n 8000 4.0 n n Sony A7R
Canon 1D X Mark II« »optical Y 3.2 1620 fixed Y 8000 16.0 n n Canon 1D X Mark II
Canon 1D X« »optical Y 3.2 1040 fixed n 8000 14.0 n n Canon 1D X
Canon 1D Mark IV« »optical Y 3.0 920 fixed n 8000 10.0 n n Canon 1D Mark IV
Leica S Typ 006« »optical Y 3.0 922 fixed n 4000 1.5 n n Leica S Typ 006
Nikon D850« »optical Y 3.2 2359 tilting Y 8000 9.0 n n Nikon D850
Nikon D5« »optical Y 3.2 2359 fixed Y 8000 14.0 n n Nikon D5
Nikon D810« »optical Y 3.2 1229 fixed n 8000 5.0 Y n Nikon D810
Nikon D3S« »optical Y 3.0 921 fixed n 8000 11.0 n n Nikon D3S
Pentax 645Z« »optical Y 3.2 1037 tilting n 4000 3.0 n n Pentax 645Z
Sony A7R II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7R II
Sony A7 II« »2400 n 3.0 1230 tilting n 8000 5.0 n Y Sony A7 II
Sony A7S« »2400 n 3.0 921 tilting n 8000 5.0 n n Sony A7S
Sony A7« »2400 n 3.0 1230 tilting n 8000 5.0 n n Sony A7

One feature that is present on the 645D, but is missing on the A7R is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.

The 645D writes its imaging data to SDXC cards, while the A7R uses SDXC or Memory Stick PRO Duo cards. The 645D features dual card slots, which can be very useful in case a memory card fails. In contrast, the A7R 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
Pentax 645D»Ystereo----2.0---Pentax 645D
Sony A7R«YstereomonoYYmicro2.0YY-Sony A7R
Canon 1D X Mark II« »YmonomonoYYmini3.0---Canon 1D X Mark II
Canon 1D X« »Ymono-Y-mini2.0---Canon 1D X
Canon 1D Mark IV« »Ystereo-Y-mini2.0---Canon 1D Mark IV
Leica S Typ 006« »Y----mini2.0---Leica S Typ 006
Nikon D850« »YstereomonoYYmini3.0YYYNikon D850
Nikon D5« »YstereomonoYYmini3.0---Nikon D5
Nikon D810« »YstereomonoYYmini3.0Y--Nikon D810
Nikon D3S« »Ystereo---mini2.0---Nikon D3S
Pentax 645Z« »YstereomonoY-mini3.0---Pentax 645Z
Sony A7R II« »YstereomonoYYmicro2.0YY-Sony A7R II
Sony A7 II« »YstereomonoYYmicro2.0YY-Sony A7 II
Sony A7S« »YstereomonoYYmicro2.0YY-Sony A7S
Sony A7« »YstereomonoYYmicro2.0YY-Sony A7

Both the 645D and the A7R have been discontinued, but can regularly be found used on eBay. The 645D was replaced by the Pentax 645Z, while the A7R was followed by the Sony A7R II.

Review summary: Pentax 645D vs Sony A7R

So how do things add up? Which of the two cameras – the Pentax 645D or the Sony A7R – has the upper hand? The listing below highlights the relative strengths of the two models.

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Arguments in favor of the Pentax 645D:

  • Brighter framing: Features an optical viewfinder for clear, lag-free composition.
  • Easier setting verification: Features an LCD display on top to control shooting parameters.
  • Longer lasting: Can take more shots (800 versus 340) on a single battery charge.
  • Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
  • More heavily discounted: Has been available for much longer (launched in March 2010).

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Advantages of the Sony Alpha A7R:

  • Better image quality: Scores substantially higher (13 points) in the DXO overall evaluation.
  • More dynamic range: Captures a broader range of light and dark details (1.5 EV of extra DR).
  • Better low-light sensitivity: Can shoot in dim conditions (1.1 stops ISO advantage).
  • Broader imaging potential: Can capture not only stills but also 1080/60p video.
  • More framing info: Has an electronic viewfinder that displays shooting data.
  • More detailed LCD: Has a higher resolution rear screen (1230k vs 921k dots).
  • More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
  • Faster shutter: Has higher mechanical shutter speed (8000/sec vs 4000/sec) to freeze action.
  • Faster burst: Shoots at higher frequency (4 vs 1.1 flaps/sec) to capture the decisive moment.
  • More compact: Is smaller (127x94mm vs 156x117mm) and will fit more readily into a bag.
  • Less heavy: Has a lower weight (by 1015g or 69 percent) and is thus easier to take along.
  • More legacy lens friendly: Can use many 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 (77 percent cheaper at launch).
  • More modern: Reflects 3 years and 7 months of technical progress since the 645D launch.

If the number of relative strengths (bullet points above) is taken as a guide, the A7R is the clear winner of the contest (16 : 5 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.

645D 05:16 A7R

In any case, while the comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it remains partial and cannot reveal, for example, the handling experience and imaging performance when actually working with the 645D or the A7R. 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 expert reviews 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
Pentax 645D»---4.5/5- Mar 2010 9,995- i Pentax 645D
Sony A7R«HiRec82/1004.5/55/55/5 Oct 2013 2,299- i Sony A7R
Canon 1D X Mark II« »-89/1004.5/55/54.5/5 Feb 2016 5,999 i i Canon 1D X Mark II
Canon 1D X« »--4.5/54.5/54.5/5 Oct 2011 6,799- i Canon 1D X
Canon 1D Mark IV« »-89/100-5/5- Oct 2009 4,999- i Canon 1D Mark IV
Leica S Typ 006« »----- Sep 2012 21,950- i Leica S Typ 006
Nikon D850« »HiRec89/1004.5/55/55/5 Jul 2017 3,299 i i Nikon D850
Nikon D5« »-89/1004.5/55/55/5 Jan 2016 6,499 i i Nikon D5
Nikon D810« »-86/1005/54.5/54.5/5 Jun 2014 3,299- i Nikon D810
Nikon D3S« »-89/1004.5/55/55/5 Oct 2009 5,199- i Nikon D3S
Pentax 645Z« »--4.5/55/55/5 Apr 2014 8,499 i i Pentax 645Z
Sony A7R II« »HiRec90/1005/54.5/55/5 Jun 2015 3,199- i Sony A7R II
Sony A7 II« »Rec82/1004.5/55/55/5 Nov 2014 1,999- i Sony A7 II
Sony A7S« »-86/1004.5/54.5/55/5 Apr 2014 2,499- i Sony A7S
Sony A7« »HiRec80/1005/54.5/55/5 Oct 2013 1,699- i Sony A7

Care should be taken when interpreting the review scores above, though. The ratings are only valid when referring to cameras in the same category and of the same age. 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, please note that some of the review sites have changed their methodology and reporting over time.

 

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. 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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