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Pentax K-1 versus Sony A7R III

The Pentax K-1 and the Sony Alpha A7R III are two enthusiast cameras that were announced, respectively, in February 2016 and October 2017. The K-1 is a DSLR, while the A7R III is a mirrorless interchangeable lens camera. Both cameras are equipped with a full frame sensor. The Pentax has a resolution of 36.2 megapixel, whereas the Sony provides 42.2 MP.

Body comparison

The physical size and weight of the Pentax K-1 and the Sony A7R III are illustrated in the side-by-side display below. Three consecutive perspectives from the front, the top, and the back are presented. 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 K-1 – represents the basis or 100 percent across all the size and weight measures).

Pentax K-1 vs Sony A7R III front
K-1 versus A7R III top view
K-1 and A7R III rear side
Body view (K-1 on the left)

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7R III is notably smaller (19 percent) than the Pentax K-1. Moreover, the A7R III is substantially lighter (36 percent) than the K-1. 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 K-1 (⇒ rgt) 137 mm 110 mm 86 mm 1010 g 760 YES 2016 1,799 latest check
Sony A7R III (⇒ lft) 127 mm 96 mm 74 mm 650 g 650 YES 2017 3,199 latest check
Canon 6D Mark II (⇒ lft | rgt) 144 mm 111 mm 75 mm 765 g 1200 YES 2017 1,999 latest check
Canon 5D Mark IV (⇒ lft | rgt) 151 mm 116 mm 76 mm 890 g 900 YES 2016 3,499 latest check
Nikon D850 (⇒ lft | rgt) 146 mm 124 mm 79 mm 1005 g 1840 YES 2017 3,299 latest check
Nikon D500 (⇒ lft | rgt) 147 mm 115 mm 81 mm 860 g 1240 YES 2016 1,999 latest check
Olympus E-M1 II (⇒ lft | rgt) 134 mm 91 mm 67 mm 574 g 440 YES 2016 1,999 latest check
Panasonic GH5 (⇒ lft | rgt) 139 mm 98 mm 87 mm 725 g 410 YES 2017 1,999 latest check
Pentax K-3 II (⇒ lft | rgt) 131 mm 100 mm 77 mm 800 g 720 YES 2015 1,099 latest check
Sony A9 (⇒ lft | rgt) 127 mm 96 mm 63 mm 673 g 650 YES 2017 4,499 latest check
Sony A99 II (⇒ lft | rgt) 143 mm 104 mm 76 mm 849 g 490 YES 2016 3,199 latest check
Sony A6500 (⇒ lft | rgt) 120 mm 67 mm 53 mm 453 g 350 YES 2016 1,399 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

The listed prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The K-1 was launched at a markedly lower price (by 44 percent) than the A7R III, 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 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. Moreover, a large sensor camera will give the photographer more control over depth-of-field in the image and, thus, the ability to better isolate a subject from the background. On the downside, larger sensors are more costly to manufacture and tent to lead to bigger and heavier cameras and lenses.

Both cameras under consideration feature a full frame sensor and have a format factor (sometimes also referred to as "crop factor") of 1.0. Within the spectrum of camera sensors, this places the review cameras among the large-sensor cameras that aim for top notch image quality. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Pentax K-1 and Sony A7R III sensor measures
Sensor size
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Sensor size

While the two cameras under review share the same sensor size, the A7R III offers a higher resolution of 42.2 megapixel, compared with 36.2 MP of the K-1. This megapixel advantage translates into a 8 percent gain in linear resolution. On the other hand, these sensor specs imply that the A7R III has a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 4.52μm versus 4.88μm for the K-1). However, it should be noted that the A7R III is a somewhat more recent model (by 1 year and 8 months) than the K-1, and its sensor might have benefitted from technological advances during this time that at least partly compensate for the smaller pixel size. 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.

Both cameras have the capacity to capture high quality composite images by combining multiple shots after shifting the sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).

K-1 versus A7R III MP
Sensor resolution
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Sensor resolution

For most cameras, data on sensor performance has been reported by DXO Mark. This service determines an overall sensor rating, as well as sub-scores for low-light sensitivity ("DXO Sports"), dynamic range ("DXO Landscape"), and color depth ("DXO Portrait"). 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 Sensor
Class
Resolution
(Megapixel)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Pentax K-1 (⇒ rgt) Full Frame 36.2 7360 4912 1080/60i 25.4 14.6 3280 96
Sony A7R III (⇒ lft) Full Frame 42.2 7952 5304 4K/30p .. .. .. ..
Canon 6D Mark II (⇒ lft | rgt) Full Frame 26.0 6240 4160 1080/60p 24.4 11.9 2862 85
Canon 5D Mark IV (⇒ lft | rgt) Full Frame 30.1 6720 4480 4K/30p 24.8 13.6 2995 91
Nikon D850 (⇒ lft | rgt) Full Frame 45.4 8256 5504 4K/30p 26.4 14.8 2660 100
Nikon D500 (⇒ lft | rgt) APS-C 20.7 5568 3712 4K/30p 24.0 14.0 1324 83
Olympus E-M1 II (⇒ lft | rgt) Four Thirds 20.2 5184 3888 4K/30p 23.7 12.8 1312 80
Panasonic GH5 (⇒ lft | rgt) Four Thirds 20.2 5184 3888 4K/60p 23.9 13.0 807 77
Pentax K-3 II (⇒ lft | rgt) APS-C 24.1 6016 4000 1080/60i 23.6 13.6 1106 80
Sony A9 (⇒ lft | rgt) Full Frame 24.0 6000 4000 4K/30p 24.9 13.3 3517 92
Sony A99 II (⇒ lft | rgt) Full Frame 42.2 7952 5304 4K/30p 25.4 13.4 2317 92
Sony A6500 (⇒ lft | rgt) APS-C 24.0 6000 4000 4K/30p 24.5 13.7 1405 85
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

Many modern cameras are not only capable of taking still images, but also of capturing video footage. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the A7R III provides a better video resolution than the K-1. It can shoot movie footage at 4K/30p, while the Pentax is limited to 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the A7R III has an electronic viewfinder (3686k dots), while the K-1 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 Pentax K-1, the Sony A7R III, 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
Pentax K-1 (⇒ rgt) optical YES 3.2 1037 full-flex no 8000 4.4 no YES
Sony A7R III (⇒ lft) 3686 no 3.0 1440 tilting YES 8000 10.0 no YES
Canon 6D Mark II (⇒ lft | rgt) optical YES 3.0 1040 swivel YES 4000 6.5 no no
Canon 5D Mark IV (⇒ lft | rgt) optical YES 3.2 1620 fixed YES 8000 7.0 no no
Nikon D850 (⇒ lft | rgt) optical YES 3.2 2359 tilting YES 8000 9.0 no no
Nikon D500 (⇒ lft | rgt) optical YES 3.2 2359 tilting YES 8000 10.0 no no
Olympus E-M1 II (⇒ lft | rgt) 2360 no 3.0 1037 swivel YES 8000 18.0 no YES
Panasonic GH5 (⇒ lft | rgt) 3680 no 3.2 1620 swivel YES 8000 12.0 no YES
Pentax K-3 II (⇒ lft | rgt) optical YES 3.2 1037 fixed no 8000 8.3 no YES
Sony A9 (⇒ lft | rgt) 3686 no 3.0 1440 tilting YES 8000 20.0 no YES
Sony A99 II (⇒ lft | rgt) 2400 YES 3.0 1229 tilting no 8000 12.0 no YES
Sony A6500 (⇒ lft | rgt) 2300 no 3.0 922 tilting YES 4000 11.0 6 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

Both the K-1 and the A7R III are current models that good online retailers will have in stock. You can check the latest prices, for example, at amazon. The A7R III replaced the earlier Sony A7R II, while the K-1 does not have a direct predecessor.

Summary

So how do things add up? Which of the two cameras – the Pentax K-1 or the Sony A7R III – has the upper hand? A synthesis of the relative strong points of each of the models is listed below.


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Reasons to prefer the Pentax K-1:

  • Brighter framing: Features an optical viewfinder for clear, lag-free composition.
  • Easier setting verification: Has an LCD display on top to control shooting parameters.
  • Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
  • More flexible LCD: Has a full-flex screen for odd-angle shots in portrait or landscape orientation.
  • Longer lasting: Can take more shots (760 versus 650) on a single battery charge.
  • More affordable: Was introduced into a lower priced category (44 percent cheaper at launch).
  • More heavily discounted: Has been on the market for longer (launched in February 2016).

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Advantages of the Sony Alpha A7R III:

  • More detail: Has more megapixels (42.2 vs 36.2MP), which boosts linear resolution by 8%.
  • Better video: Provides higher definition movie capture (4K/30p vs 1080/60i).
  • More framing info: Has an electronic viewfinder that displays shooting data.
  • More detailed LCD: Has a higher resolution rear screen (1440k vs 1037k dots).
  • Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
  • Faster burst: Shoots at higher frequency (10 vs 4.4 flaps/sec) to capture the decisive moment.
  • More compact: Is smaller (127x96mm vs 137x110mm) and will fit more readily into a bag.
  • Less heavy: Has a lower weight (by 360g or 36 percent) and is thus easier to take along.
  • More legacy lens friendly: Can use many non-native lenses via adapters.
  • More modern: Was introduced somewhat (1 year and 8 months) more recently.

If the number of relative strengths (bullet points above) is taken as a guide, the A7R III emerges as the winner of the match-up (10 : 7 points). However, the pertinence of the various camera strengths will differ across photographers, so that you might want to weigh individual camera traits according to their importance for your own imaging needs.

K-1 07:10 A7R III

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 K-1 and the A7R III 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 full reviews are available, 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 K-1 (⇒ rgt) - 84/100 Silver 5/5 4.5/5 5/5 2016 1,799 latest check
Sony A7R III (⇒ lft) .. .. .. .. .. 2017 3,199 latest check
Canon 6D Mark II (⇒ lft | rgt) Rec 80/100 4.5/5 4/5 4/5 2017 1,999 latest check
Canon 5D Mark IV (⇒ lft | rgt) HiRec 87/100 Gold 4.5/5 5/5 4.5/5 2016 3,499 latest check
Nikon D850 (⇒ lft | rgt) .. 89/100 Gold 4.5/5 .. 5/5 2017 3,299 latest check
Nikon D500 (⇒ lft | rgt) HiRec 91/100 Gold 4.5/5 5/5 5/5 2016 1,999 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
Panasonic GH5 (⇒ lft | rgt) HiRec 85/100 Gold 4.5/5 5/5 5/5 2017 1,999 latest check
Pentax K-3 II (⇒ lft | rgt) - - 5/5 4.5/5 5/5 2015 1,099 latest check
Sony A9 (⇒ lft | rgt) .. 89/100 Gold 5/5 5/5 5/5 2017 4,499 latest check
Sony A99 II (⇒ lft | rgt) - 85/100 Silver 4.5/5 4.5/5 4.5/5 2016 3,199 latest check
Sony A6500 (⇒ lft | rgt) HiRec 85/100 Silver 4.5/5 5/5 4.5/5 2016 1,399 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

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

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 update the database with the necessary infos.

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