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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 officially introduced, 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 views from the front, the top, and the rear side are shown. All width, height and depth 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 K-1 – represents the basis for the calculations 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.

Concerning battery life, the K-1 gets 760 shots out of its D-LI90 battery, while the A7R III can take 650 images on a single charge of its NP-FZ100 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 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 5D Mark IV (⇒ lft | rgt) 151 mm 116 mm 76 mm 890 g 900 YES 2016 3,499 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-1 II (⇒ lft | rgt) 137 mm 110 mm 86 mm 1010 g 670 YES 2018 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 A7 III (⇒ lft | rgt) 127 mm 96 mm 74 mm 650 g 610 YES 2018 1,999 latest check
Sony A99 II (⇒ lft | rgt) 143 mm 104 mm 76 mm 849 g 490 YES 2016 3,199 latest check
Sony A7R II (⇒ lft | rgt) 127 mm 96 mm 60 mm 625 g 290 YES 2015 3,199discont. check
Sony A7 II (⇒ lft | rgt) 127 mm 96 mm 60 mm 599 g 350 YES 2014 1,999discont. check
Sony A7R (⇒ lft | rgt) 127 mm 94 mm 48 mm 465 g 340 YES 2013 2,299discont. check
Sony A850 (⇒ lft | rgt) 156 mm 117 mm 82 mm 895 g 880 YES 2009 1,999discont. 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 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 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.

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

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

Consistent information on actual sensor performance is available from DXO Mark for most 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 III has a markedly higher DXO score than the K-1 (overall score 4 points higher), which will translate into better image quality. The advantage is based on 0.6 bits higher color depth, 0.1 EV in additional dynamic range, and 0.1 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 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 26.0 14.7 3523 100
Canon 5D Mark IV (⇒ lft | rgt) Full Frame 30.1 6720 4480 4K/30p 24.8 13.6 2995 91
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-1 II (⇒ lft | rgt) Full Frame 36.2 7360 4912 1080/60i .. .. .. ..
Pentax K-3 II (⇒ lft | rgt) APS-C 24.1 6016 4000 1080/60i 23.6 13.6 1106 80
Sony A7 III (⇒ lft | rgt) Full Frame 24.0 6000 4000 4K/30p 25.0 14.7 3730 96
Sony A99 II (⇒ lft | rgt) Full Frame 42.2 7952 5304 4K/30p 25.4 13.4 2317 92
Sony A7R II (⇒ lft | rgt) Full Frame 42.2 7952 5304 4K/30p 26.0 13.9 3434 98
Sony A7 II (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 24.9 13.6 2449 90
Sony A7R (⇒ lft | rgt) Full Frame 36.2 7360 4912 1080/60p 25.6 14.1 2746 95
Sony A850 (⇒ lft | rgt) Full Frame 24.4 6048 4032 no 23.8 12.2 1415 79

Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, 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

Beyond 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 adjacent table lists some of the other core features of the Pentax K-1 and Sony A7R III along with similar information for a selection of comparators. The full specs-sheets can be found in the camera manual or, 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 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 5D Mark IV (⇒ lft | rgt) optical YES 3.2 1620 fixed YES 8000 7.0 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-1 II (⇒ lft | rgt) optical YES 3.2 1037 full-flex no 8000 4.4 no YES
Pentax K-3 II (⇒ lft | rgt) optical YES 3.2 1037 fixed no 8000 8.3 no YES
Sony A7 III (⇒ lft | rgt) 2359 no 3.0 922 tilting YES 8000 10 no YES
Sony A99 II (⇒ lft | rgt) 2400 YES 3.0 1229 full-flex no 8000 12.0 no YES
Sony A7R II (⇒ lft | rgt) 2400 no 3.0 1229 tilting no 8000 5.0 no YES
Sony A7 II (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 5.0 no YES
Sony A7R (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 4.0 no no
Sony A850 (⇒ lft | rgt) optical YES 3.0 922 fixed no 8000 3.0 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? The listing below highlights the relative strengths of the two models.


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Arguments in favor of 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 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 image quality: Scores markedly higher (4 points) in the DXO overall evaluation.
  • 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 is the clear winner of the contest (11 : 7 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.

K-1 07:11 A7R III

In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it remains partial and cannot reveal, for example, the handling experience and imaging performance when actually working with the K-1 or the A7R III. 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. The detailed reviews can be accessed, respectively, on the websites of 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) HiRec 90/100 Gold 4.5/5 5/5 5/5 2017 3,199 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 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-1 II (⇒ lft | rgt) - .. 4.5/5 .. 4.5/5 2018 1,999 latest check
Pentax K-3 II (⇒ lft | rgt) - - 5/5 4.5/5 5/5 2015 1,099 latest check
Sony A7 III (⇒ lft | rgt) HiRec 89/100 Gold 5/5 .. 5/5 2018 1,999 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 A7R II (⇒ lft | rgt) HiRec 90/100 Gold 5/5 4.5/5 5/5 2015 3,199discont. check
Sony A7 II (⇒ lft | rgt) Rec 82/100 Silver 4.5/5 5/5 5/5 2014 1,999discont. check
Sony A7R (⇒ lft | rgt) HiRec 82/100 Gold 4.5/5 5/5 5/5 2013 2,299discont. check
Sony A850 (⇒ lft | rgt) - 75/100 - 4/5 4.5/5 2009 1,999discont. check

The review scores listed above should be treated with care, though. The ratings are only valid when refering to cameras in the same category and of the same age. Hence, a score should always be seen in the context of the camera's market launch date and its price, 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 comparisons

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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