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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. 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 K-1 vs Sony A7R III

The physical size and weight of the Pentax K-1 and the Sony A7R III are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear 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 side – the K-1 – represents the basis for the calculations across all the size and weight measures).

Compare Pentax K-1 vs Sony A7R III
Compare K-1 versus A7R III top
Compare K-1 and A7R III rear

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. 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 K-1» 5.4 in 4.3 in 3.4 in 35.6 oz 760 Y Feb 2016 1,799- i Pentax K-1
Sony A7R III« 5.0 in 3.8 in 2.9 in 22.9 oz 650 Y Oct 2017 3,199 i i Sony A7R III
Canon 5D Mark IV« » 5.9 in 4.6 in 3.0 in 31.4 oz 900 Y Aug 2016 3,499 i i Canon 5D Mark IV
Nikon D500« » 5.8 in 4.5 in 3.2 in 30.3 oz 1240 Y Jan 2016 1,999 i i Nikon D500
Olympus E-M1 II« » 5.3 in 3.6 in 2.6 in 20.2 oz 440 Y Sep 2016 1,999 i i Olympus E-M1 II
Pentax K-1 II« » 5.4 in 4.3 in 3.4 in 35.6 oz 670 Y Feb 2018 1,999 i i Pentax K-1 II
Pentax K-3 II« » 5.2 in 3.9 in 3.0 in 28.2 oz 720 Y Apr 2015 1,099 i i Pentax K-3 II
Sony A7 III« » 5.0 in 3.8 in 2.9 in 22.9 oz 610 Y Feb 2018 1,999 i i Sony A7 III
Sony A9« » 5.0 in 3.8 in 2.5 in 23.7 oz 650 Y Apr 2017 4,499 i i Sony A9
Sony A99 II« » 5.6 in 4.1 in 3.0 in 29.9 oz 490 Y Sep 2016 3,199 i i Sony A99 II
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 A7S II« » 5.0 in 3.8 in 2.4 in 22.1 oz 370 Y Sep 2015 2,999 i i Sony A7S II
Sony A850« » 6.1 in 4.6 in 3.2 in 31.6 oz 880 Y Aug 2009 1,999- i Sony A850

The price is, of course, an important factor in any camera decision. The retail prices at the time of the camera’s release place the model in the market relative to other models in the producer’s line-up and the competition. 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. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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 K-1 vs Sony A7R III

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. 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 tend 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

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

Consistent information on actual sensor performance is available from DXO Mark for many cameras. 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 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 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
Model
Sensor
Class
Resolution
(MP)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Camera
Model
Pentax K-1» Full Frame 36.2 7360 49121080/60i25.414.6328096Pentax K-1
Sony A7R III« Full Frame 42.2 7952 53044K/30p26.014.73523100Sony A7R III
Canon 5D Mark IV« » Full Frame 30.1 6720 44804K/30p24.813.6299591Canon 5D Mark IV
Nikon D500« » APS-C 20.7 5568 37124K/30p24.014.0132483Nikon D500
Olympus E-M1 II« » Four Thirds 20.2 5184 38884K/30p23.712.8131280Olympus E-M1 II
Pentax K-1 II« » Full Frame 36.2 7360 49121080/60i----Pentax K-1 II
Pentax K-3 II« » APS-C 24.1 6016 40001080/60i23.613.6110680Pentax K-3 II
Sony A7 III« » Full Frame 24.0 6000 40004K/30p25.014.7373096Sony A7 III
Sony A9« » Full Frame 24.0 6000 40004K/30p24.913.3351792Sony A9
Sony A99 II« » Full Frame 42.2 7952 53044K/30p25.413.4231792Sony A99 II
Sony A7R II« » Full Frame 42.2 7952 53044K/30p26.013.9343498Sony A7R II
Sony A7S II« » Full Frame 12.0 4240 28324K/30p23.613.3299385Sony A7S II
Sony A850« » Full Frame 24.4 6048 4032-23.812.2141579Sony A850

Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration have a sensor with sufficiently fast read-out times for 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: Pentax K-1 vs Sony A7R III

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 table below summarizes some of the other core capabilities of the Pentax K-1 and Sony A7R III in connection with corresponding information for a sample of similar cameras. If needed, the dpreview camera hub, for example, contains further detail on the cameras' specs.

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 K-1»optical Y 3.2 1037 full-flex n 8000 4.4 n Y Pentax K-1
Sony A7R III«3686 n 3.0 1440 tilting Y 8000 10.0 n Y Sony A7R III
Canon 5D Mark IV« »optical Y 3.2 1620 fixed Y 8000 7.0 n n Canon 5D Mark IV
Nikon D500« »optical Y 3.2 2359 tilting Y 8000 10.0 n n Nikon D500
Olympus E-M1 II« »2360 n 3.0 1037 swivel Y 8000 18.0 n Y Olympus E-M1 II
Pentax K-1 II« »optical Y 3.2 1037 full-flex n 8000 4.4 n Y Pentax K-1 II
Pentax K-3 II« »optical Y 3.2 1037 fixed n 8000 8.3 n Y Pentax K-3 II
Sony A7 III« »2359 n 3.0 922 tilting Y 8000 10.0 n Y Sony A7 III
Sony A9« »3686 n 3.0 1440 tilting Y 8000 20.0 n Y Sony A9
Sony A99 II« »2400 Y 3.0 1229 full-flex n 8000 12.0 n Y Sony A99 II
Sony A7R II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7R II
Sony A7S II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7S II
Sony A850« »optical Y 3.0 922 fixed n 8000 3.0 n Y Sony A850

One feature that is present on the K-1, but is missing on the A7R III 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 reported shutter speed and shutter burst refer to the use of the mechanical shutter. In addition, the A7R III features an electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (rolling shutter) or shooting under artificial light sources (flickering).

The K-1 writes its imaging data to SDXC cards, while the A7R III uses SDXC or Memory Stick PRO Duo cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails.

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 K-1»YstereomonoYYmicro2.0Y--Pentax K-1
Sony A7R III«YstereomonoYYmicro3.1YYYSony A7R III
Canon 5D Mark IV« »YmonomonoYYmini3.0YY-Canon 5D Mark IV
Nikon D500« »YstereomonoYYmini3.0YYYNikon D500
Olympus E-M1 II« »YstereomonoYYmicro3.0Y--Olympus E-M1 II
Pentax K-1 II« »YstereomonoYYmicro2.0Y--Pentax K-1 II
Pentax K-3 II« »YmonomonoYYmini3.0---Pentax K-3 II
Sony A7 III« »YstereomonoYYmicro3.1YYYSony A7 III
Sony A9« »YstereomonoYYmicro2.0YYYSony A9
Sony A99 II« »YstereomonoYYmicro2.0YYYSony A99 II
Sony A7R II« »YstereomonoYYmicro2.0YY-Sony A7R II
Sony A7S II« »YstereomonoYYmicro2.0YY-Sony A7S II
Sony A850« »Y----mini2.0---Sony A850

The A7R III is a current model that online retailers, such as amazon, will have in stock. In contrast, the K-1 has been discontinued (but it can be found pre-owned on eBay). As a replacement in the same line of cameras, the K-1 was succeeded by the Pentax K-1 II.

Review summary: Pentax K-1 vs Sony A7R III

So what is the bottom line? Is there a clear favorite between the Pentax K-1 and the Sony A7R III? A synthesis of the relative strong points of each of the models is listed below.

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Advantages of the Pentax K-1:

  • Brighter framing: Features an optical viewfinder for clear, lag-free composition.
  • Easier setting verification: Features 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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Reasons to prefer 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.
  • Less disturbing: Has an electronic shutter option for completely silent shooting.
  • 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.
  • Faster data transfer: Supports a more advanced USB protocol (3.1 vs 2.0).
  • Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
  • Easier wireless transfer: Supports Bluetooth for image sharing without cables.
  • 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 (15 : 7 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.

K-1 07:15 A7R III

In any case, while the specs-based evaluation of cameras is instructive in revealing their potential as photographic tools, 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 hands-on reviews by experts are important. The table below summarizes the assessments of some of the best known camera review sites (cameralabs, dpreview, ephotozine, imaging-resource, photographyblog). You can find the full text of the reviews 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 K-1»-84/1005/54.5/55/5 Feb 2016 1,799- i Pentax K-1
Sony A7R III«HiRec90/1004.5/55/55/5 Oct 2017 3,199 i i Sony A7R III
Canon 5D Mark IV« »HiRec87/1004.5/55/54.5/5 Aug 2016 3,499 i i Canon 5D Mark IV
Nikon D500« »HiRec91/1004.5/55/55/5 Jan 2016 1,999 i i Nikon D500
Olympus E-M1 II« »HiRec85/1004.5/55/54.5/5 Sep 2016 1,999 i i Olympus E-M1 II
Pentax K-1 II« »-79/1004.5/5-4.5/5 Feb 2018 1,999 i i Pentax K-1 II
Pentax K-3 II« »--5/54.5/55/5 Apr 2015 1,099 i i Pentax K-3 II
Sony A7 III« »HiRec89/1005/55/55/5 Feb 2018 1,999 i i Sony A7 III
Sony A9« »HiRec89/1005/55/55/5 Apr 2017 4,499 i i Sony A9
Sony A99 II« »-85/1004.5/54.5/54.5/5 Sep 2016 3,199 i i Sony A99 II
Sony A7R II« »HiRec90/1005/54.5/55/5 Jun 2015 3,199- i Sony A7R II
Sony A7S II« »Rec-4.5/55/55/5 Sep 2015 2,999 i i Sony A7S II
Sony A850« »-75/100-4/54.5/5 Aug 2009 1,999- i Sony A850

The review scores listed above should be treated 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. 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, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

 

Other camera comparisons

Did this review help to inform your camera decision process? If you would like to see a different side-by-side camera review, just make a corresponding selection in the search boxes below. An an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool. If you cannot find the camera you are interested in, kindly get in touch, and I will try to update the database with the necessary infos.

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