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Pentax 645D versus Nikon D810

The Pentax 645D and the Nikon D810 are two professional cameras that were announced, respectively, in March 2010 and June 2014. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a medium format (645D) and a full frame sensor. The Pentax has a resolution of 39.5 megapixel, whereas the Nikon provides 36.2 MP.

Body comparison

The physical size and weight of the Pentax 645D and the Nikon D810 are illustrated in the side-by-side display below. Three consecutive views from the front, the top, and the rear side are shown. All width, height and depth dimensions are rounded to the nearest millimeter. You can also use the toggle button 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 645D – represents the basis or 100 percent across all the size and weight measures).

Pentax 645D vs Nikon D810 front
645D versus D810 top view
645D and D810 rear side
Body view (645D on the left)

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Nikon D810 is somewhat smaller (2 percent) than the Pentax 645D. Moreover, the D810 is markedly lighter (34 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.

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
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)
Pentax 645D (⇒ rgt) 6.1 in 4.6 in 4.7 in 52.2 oz .. YES 2010 9,995discont. check
Nikon D810 (⇒ lft) 5.7 in 4.8 in 3.2 in 34.6 oz 1200 YES 2014 3,299discont. check
Leica S Typ 006 (⇒ lft | rgt) 6.3 in 4.7 in 3.1 in 44.4 oz .. YES 2012 21,950discont. check
Nikon D850 (⇒ lft | rgt) 5.7 in 4.9 in 3.1 in 35.5 oz 1840 YES 2017 3,299 latest check
Nikon D750 (⇒ lft | rgt) 5.6 in 4.4 in 3.1 in 26.5 oz 1230 YES 2014 2,299 latest check
Nikon D610 (⇒ lft | rgt) 5.6 in 4.4 in 3.2 in 30.0 oz 900 YES 2013 1,999 latest check
Nikon Df (⇒ lft | rgt) 5.7 in 4.3 in 2.6 in 26.8 oz 1400 YES 2013 2,749 latest check
Nikon D800 (⇒ lft | rgt) 5.7 in 4.8 in 3.2 in 35.3 oz .. YES 2012 2,999discont. check
Nikon D800E (⇒ lft | rgt) 5.7 in 4.8 in 3.2 in 35.3 oz .. YES 2012 3,299discont. check
Nikon D7000 (⇒ lft | rgt) 5.2 in 4.1 in 3.0 in 27.5 oz 1050 YES 2010 1,499discont. check
Nikon D3S (⇒ lft | rgt) 6.3 in 6.2 in 3.5 in 43.7 oz 4200 YES 2009 5,199discont. check
Pentax K-1 (⇒ lft | rgt) 5.4 in 4.3 in 3.4 in 35.6 oz 760 YES 2016 1,799 latest check
Pentax 645Z (⇒ lft | rgt) 6.1 in 4.6 in 4.8 in 54.7 oz 650 YES 2014 8,499 latest check
Sony A7R (⇒ lft | rgt) 5.0 in 3.7 in 1.9 in 16.4 oz 340 YES 2013 2,299discont. check

The listed prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The D810 was launched at a markedly lower price (by 67 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.

Sensor comparison

The size of the sensor inside a digital camera is one of the key determinants 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. 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 are more costly to manufacture and tent to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Pentax 645D features a medium format sensor and the Nikon D810 a full frame sensor. The sensor area in the D810 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 D810 offers a 3:2 aspect.

Pentax 645D and Nikon D810 sensor measures
Sensor size

With 39.5MP, the 645D offers a higher resolution than the D810 (36.2MP), but the 645D nevertheless has larger individual pixels (pixel pitch of 6.06μm versus 4.88μm for the D810) due to its larger sensor. However, the D810 is a somewhat more recent model (by 4 years and 3 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 D810 MP
Sensor resolution

For most cameras, data on sensor performance has been reported by DXO Mark. 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 D810 offers substantially better image quality than the 645D (overall score 15 points higher). The advantage is based on 1.1 bits higher color depth, 2.2 EV in additional dynamic range, and 1.2 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.

Sensor Characteristics
Camera Sensor
Class
Resolution
(Megapixel)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Pentax 645D (⇒ rgt) Medium Format 39.5 7264 5440 no 24.6 12.6 1262 82
Nikon D810 (⇒ lft) Full Frame 36.2 7360 4912 1080/60p 25.7 14.8 2853 97
Leica S Typ 006 (⇒ lft | rgt) Medium Format 37.5 7500 5000 no 23.9 12.2 824 76
Nikon D850 (⇒ lft | rgt) Full Frame 45.4 8256 5504 4K/30p 26.4 14.8 2660 100
Nikon D750 (⇒ lft | rgt) Full Frame 24.2 6016 4016 1080/60p 24.8 14.5 2956 93
Nikon D610 (⇒ lft | rgt) Full Frame 24.2 6016 4016 1080/30p 25.1 14.4 2925 94
Nikon Df (⇒ lft | rgt) Full Frame 16.2 4928 3280 no 24.6 13.1 3279 89
Nikon D800 (⇒ lft | rgt) Full Frame 36.2 7360 4912 1080/30p 25.3 14.4 2853 95
Nikon D800E (⇒ lft | rgt) Full Frame 36.2 7360 4912 1080/30p 25.6 14.3 2979 96
Nikon D7000 (⇒ lft | rgt) APS-C 16.1 4928 3264 10800/24p 23.5 13.9 1167 80
Nikon D3S (⇒ lft | rgt) Full Frame 12.1 4256 2832 720/24p 23.5 12.0 3253 82
Pentax K-1 (⇒ lft | rgt) Full Frame 36.2 7360 4912 1080/60i 25.4 14.6 3280 96
Pentax 645Z (⇒ lft | rgt) Medium Format 51.1 8256 6192 1080/60i 26.0 14.7 4505 101
Sony A7R (⇒ lft | rgt) Full Frame 36.2 7360 4912 1080/60p 25.6 14.1 2746 95

Many modern cameras are not only capable of taking still images, but also of capturing video footage. The D810 indeed provides for movie recording, while the 645D does not. The highest resolution format that the D810 can use is 1080/60p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. The 645D and the D810 are similar in the sense that both have an optical viewfinder. The latter is useful for getting a clear image for framing even in brightly lit environments. The table below summarizes some of the other core capabilities of the Pentax 645D and Nikon D810 in connection with corresponding information for a sample of similar cameras. If you need more detail on the specs, you can find comprehensive listings, for example, in the dpreview camera hub.

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
Pentax 645D (⇒ rgt) optical YES 3.0 921 fixed no 4000 1.1 no no
Nikon D810 (⇒ lft) optical YES 3.2 1229 fixed no 4000 5.0 12 no
Leica S Typ 006 (⇒ lft | rgt) optical YES 3.0 922 fixed no 4000 1.5 no no
Nikon D850 (⇒ lft | rgt) optical YES 3.2 2359 tilting YES 8000 9.0 no no
Nikon D750 (⇒ lft | rgt) optical YES 3.2 1229 tilting no 4000 6.0 12 no
Nikon D610 (⇒ lft | rgt) optical YES 3.2 921 fixed no 4000 6.0 12 no
Nikon Df (⇒ lft | rgt) optical YES 3.2 921 fixed no 4000 5.5 no no
Nikon D800 (⇒ lft | rgt) optical YES 3.2 921 fixed no 8000 4.0 12 no
Nikon D800E (⇒ lft | rgt) optical YES 3.2 921 fixed no 8000 4.0 12 no
Nikon D7000 (⇒ lft | rgt) optical YES 3.0 921 fixed no 8000 6.0 12 no
Nikon D3S (⇒ lft | rgt) optical YES 3.0 921 fixed no 8000 11.0 no no
Pentax K-1 (⇒ lft | rgt) optical YES 3.2 1037 full-flex no 8000 4.4 no YES
Pentax 645Z (⇒ lft | rgt) optical YES 3.2 1037 tilting no 4000 3.0 no no
Sony A7R (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 4.0 no no

Both the 645D and the D810 have been discontinued, but can regularly be found used on ebay. The 645D was replaced by the Pentax 645Z, while the D810 was followed by the Nikon D850.

Summary

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


Reasons to prefer the Pentax 645D:

  • More heavily discounted: Has been available for much longer (launched in March 2010).

Advantages of the Nikon D810:

  • Better image quality: Scores substantially higher (15 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 (2.2 EV of extra DR).
  • Better low-light sensitivity: Can shoot in dim conditions (1.2 stops ISO advantage).
  • Broader imaging potential: Can capture not only stills but also 1080/60p video.
  • Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
  • More detailed LCD: Has a higher resolution rear screen (1229k vs 921k dots).
  • Faster burst: Shoots at higher frequency (5 vs 1.1 flaps/sec) to capture the decisive moment.
  • Less heavy: Has a lower weight (by 500g or 34 percent) and is thus easier to take along.
  • Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
  • More affordable: Was introduced into a lower priced category (67 percent cheaper at launch).
  • More modern: Reflects 4 years and 3 months of technical progress since the 645D launch.

If the number of relative strengths (bullet points above) is taken as a guide, the D810 is the clear winner of the contest (12 : 1 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.

645D 01:12 D810

In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it remains incomplete and does no justice, for example, to the way the 645D or the D810 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 why expert reviews are important. The table below summarizes the assessments of some of the best known camera review sites. You can find the full text of the reviews, respectively, at cameralabs.com, dpreview.com, ephotozine.com, imaging-resource.com, and photographyblog.com.

Review scores
Camera camera
labs
dp
review
ephoto
zine
imaging
resource
photography
blog
Camera
Launch
(year)
Launch
Price
(USD)
Street
Price
(amazon)
Used
Price
(ebay)
Pentax 645D (⇒ rgt) - - - 4.5/5 - 2010 9,995discont. check
Nikon D810 (⇒ lft) - 86/100 Gold 5/5 4.5/5 4.5/5 2014 3,299discont. check
Leica S Typ 006 (⇒ lft | rgt) - - - - - 2012 21,950discont. check
Nikon D850 (⇒ lft | rgt) .. 89/100 Gold 4.5/5 .. 5/5 2017 3,299 latest check
Nikon D750 (⇒ lft | rgt) HiRec 90/100 Gold 4.5/5 5/5 4.5/5 2014 2,299 latest check
Nikon D610 (⇒ lft | rgt) HiRec 87/100 Gold 4.5/5 4.5/5 4.5/5 2013 1,999 latest check
Nikon Df (⇒ lft | rgt) - 81/100 4/5 4/5 4/5 2013 2,749 latest check
Nikon D800 (⇒ lft | rgt) HiRec 82/100 Gold 5/5 5/5 5/5 2012 2,999discont. check
Nikon D800E (⇒ lft | rgt) - 84/100 Gold 5/5 4.5/5 5/5 2012 3,299discont. check
Nikon D7000 (⇒ lft | rgt) - 80/100 Silver 4.5/5 5/5 4.5/5 2010 1,499discont. check
Nikon D3S (⇒ lft | rgt) - 89/100 Gold 4.5/5 5/5 5/5 2009 5,199discont. check
Pentax K-1 (⇒ lft | rgt) - 84/100 Silver 5/5 4.5/5 5/5 2016 1,799 latest check
Pentax 645Z (⇒ lft | rgt) - - 4.5/5 5/5 5/5 2014 8,499 latest check
Sony A7R (⇒ lft | rgt) HiRec 82/100 Gold 4.5/5 5/5 5/5 2013 2,299discont. check

The above review scores should be interpreted 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. Hence, a score should always be seen in the context of the camera's market launch date and its price, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

Other comparisons

If you would like to see a different side-by-side camera review, just make a corresponding selection in the search boxes below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored. If you do not see the camera that you are looking for, please contact me, and I will try to locate and add the respective data to the application.

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