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Pentax 645D versus Nikon D850

The Pentax 645D and the Nikon D850 are two professional cameras that were officially introduced, respectively, in March 2010 and July 2017. 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 45.4 MP.

Body comparison

The side-by-side display below illustrates the physical size and weight of the Pentax 645D and the Nikon D850. 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. 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).

Pentax 645D vs Nikon D850 front
645D versus D850 top view
645D and D850 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 Pentax 645D and the Nikon D850are of equal size. However, the D850 is markedly lighter (32 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 D850 can take 1840 images on a single charge of its EN-EL15a 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 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) 156 mm 117 mm 119 mm 1480 g 800 YES 2010 9,995discont. check
Nikon D850 (⇒ lft) 146 mm 124 mm 79 mm 1005 g 1840 YES 2017 3,299 latest check
Canon 1D X Mark II (⇒ lft | rgt) 158 mm 168 mm 83 mm 1530 g 1210 YES 2016 5,999 latest check
Canon 1D X (⇒ lft | rgt) 158 mm 168 mm 83 mm 1551 g 1120 YES 2011 6,799discont. check
Canon 1D Mark IV (⇒ lft | rgt) 156 mm 157 mm 80 mm 1230 g 1500 YES 2009 4,999discont. check
Leica S Typ 006 (⇒ lft | rgt) 160 mm 120 mm 80 mm 1260 g .. YES 2012 21,950discont. check
Nikon D5 (⇒ lft | rgt) 160 mm 159 mm 92 mm 1415 g 3780 YES 2016 6,499 latest check
Nikon D500 (⇒ lft | rgt) 147 mm 115 mm 81 mm 860 g 1240 YES 2016 1,999 latest check
Nikon D810 (⇒ lft | rgt) 146 mm 123 mm 82 mm 980 g 1200 YES 2014 3,299discont. check
Nikon D610 (⇒ lft | rgt) 141 mm 113 mm 82 mm 850 g 900 YES 2013 1,999 latest check
Nikon Df (⇒ lft | rgt) 144 mm 110 mm 67 mm 760 g 1400 YES 2013 2,749 latest check
Nikon D3S (⇒ lft | rgt) 160 mm 157 mm 88 mm 1240 g 4200 YES 2009 5,199discont. check
Pentax 645Z (⇒ lft | rgt) 156 mm 117 mm 123 mm 1550 g 650 YES 2014 8,499 latest check
Sony A7R (⇒ lft | rgt) 127 mm 94 mm 48 mm 465 g 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 D850 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. 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 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 Nikon D850 a full frame sensor. The sensor area in the D850 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 D850 offers a 3:2 aspect.

Pentax 645D and Nikon D850 sensor measures
Sensor size

Despite having a smaller sensor, the D850 offers a higher resolution of 45.4 megapixel, compared with 39.5 MP of the 645D. This megapixel advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 4.35μm versus 6.06μm for the 645D). However, it should be noted that the D850 is much more recent (by 7 years and 4 months) than the 645D, and its sensor will have benefitted from technological advances during this time that make it possible to gather light more efficiently. 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 D850 MP
Sensor resolution

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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 D850 offers substantially better image quality than the 645D (overall score 18 points higher). The advantage is based on 1.8 bits higher color depth, 2.2 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 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 D850 (⇒ lft) Full Frame 45.4 8256 5504 4K/30p 26.4 14.8 2660 100
Canon 1D X Mark II (⇒ lft | rgt) Full Frame 20.0 5472 3648 4K/60p 24.1 13.5 3207 88
Canon 1D X (⇒ lft | rgt) Full Frame 17.9 5184 3456 1080/30p 23.8 11.8 2786 82
Canon 1D Mark IV (⇒ lft | rgt) APS-H 16.0 4896 3264 1080/30p 22.8 12.0 1320 74
Leica S Typ 006 (⇒ lft | rgt) Medium Format 37.5 7500 5000 no 23.9 12.2 824 76
Nikon D5 (⇒ lft | rgt) Full Frame 20.7 5588 3712 4K/30p 25.1 12.3 2343 88
Nikon D500 (⇒ lft | rgt) APS-C 20.7 5568 3712 4K/30p 24.0 14.0 1324 83
Nikon D810 (⇒ lft | rgt) Full Frame 36.2 7360 4912 1080/60p 25.7 14.8 2853 97
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 D3S (⇒ lft | rgt) Full Frame 12.1 4256 2832 720/24p 23.5 12.0 3253 82
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 can also record movies. The D850 indeed provides for movie recording, while the 645D does not. The highest resolution format that the D850 can use is 4K/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The 645D and the D850 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 D850 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 D850 (⇒ lft) optical YES 3.2 2359 tilting YES 8000 9.0 no no
Canon 1D X Mark II (⇒ lft | rgt) optical YES 3.2 1620 fixed YES 8000 16.0 no no
Canon 1D X (⇒ lft | rgt) optical YES 3.2 1040 fixed no 8000 14.0 no no
Canon 1D Mark IV (⇒ lft | rgt) optical YES 3.0 920 fixed no 8000 10.0 no no
Leica S Typ 006 (⇒ lft | rgt) optical YES 3.0 922 fixed no 4000 1.5 no no
Nikon D5 (⇒ lft | rgt) optical YES 3.2 2359 fixed YES 8000 14.0 no no
Nikon D500 (⇒ lft | rgt) optical YES 3.2 2359 tilting YES 8000 10.0 no no
Nikon D810 (⇒ lft | rgt) optical YES 3.2 1229 fixed no 4000 5.0 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 D3S (⇒ lft | rgt) optical YES 3.0 921 fixed no 8000 11.0 no no
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

The D850 is a current model that online retailers, such as amazon, will have in stock. In contrast, the 645D has been discontinued (but it can be found pre-owned on ebay). As a replacement in the same line of cameras, the 645D was succeeded by the Pentax 645Z.

Summary

So how do things add up? Is there a clear favorite between the Pentax 645D and the Pentax 645D? Below is a summary of the relative strengths of each of the two contestants.


Advantages of the Pentax 645D:

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

Reasons to prefer the Nikon D850:

  • More detail: Has more megapixels (45.4 vs 39.5MP), which boosts linear resolution by 9%.
  • Better image quality: Scores substantially higher (18 points) in the DXO overall evaluation.
  • Richer colors: Generates noticeably more natural colors (1.8 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 (1.1 stops ISO advantage).
  • Broader imaging potential: Can capture not only stills but also 4K/30p 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 (2359k vs 921k dots).
  • More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
  • Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
  • Faster shutter: Has higher mechanical shutter speed (8000/sec vs 4000/sec) to freeze action.
  • Faster burst: Shoots at higher frequency (9 vs 1.1 flaps/sec) to capture the decisive moment.
  • Less heavy: Has a lower weight (by 475g or 32 percent) and is thus easier to take along.
  • Longer lasting: Gets more shots (1840 versus 800) out of a single battery charge.
  • More affordable: Was introduced into a lower priced category (67 percent cheaper at launch).
  • More modern: Reflects 7 years and 4 months of technical progress since the 645D launch.

If the count of individual advantages (bullet points above) is taken as a guide, the D850 is the clear winner of the contest (16 : 1 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features.

645D 01:16 D850

In any case, while the comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it remains incomplete and does no justice, for example, to the way the 645D or the D850 handle or perform in practice. 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 adjacent table relays the overall verdicts of several of the most popular 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 D850 (⇒ lft) HiRec 89/100 Gold 4.5/5 5/5 5/5 2017 3,299 latest check
Canon 1D X Mark II (⇒ lft | rgt) - 89/100 Gold 4.5/5 5/5 4.5/5 2016 5,999 latest check
Canon 1D X (⇒ lft | rgt) - - 4.5/5 4.5/5 4.5/5 2011 6,799discont. check
Canon 1D Mark IV (⇒ lft | rgt) - 89/100 Gold - 5/5 - 2009 4,999discont. check
Leica S Typ 006 (⇒ lft | rgt) - - - - - 2012 21,950discont. check
Nikon D5 (⇒ lft | rgt) - 89/100 Gold 4.5/5 5/5 5/5 2016 6,499 latest check
Nikon D500 (⇒ lft | rgt) HiRec 91/100 Gold 4.5/5 5/5 5/5 2016 1,999 latest check
Nikon D810 (⇒ lft | rgt) - 86/100 Gold 5/5 4.5/5 4.5/5 2014 3,299discont. 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 D3S (⇒ lft | rgt) - 89/100 Gold 4.5/5 5/5 5/5 2009 5,199discont. 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 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 comparisons

In case you are interested in seeing how other cameras pair up, just make a corresponding selection in the search boxes 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 contact me, and I will try to locate and add the respective data to the application.

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