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Pentax K-3 vs Sony A9

The Pentax K-3 and the Sony Alpha A9 are two digital cameras that were revealed to the public, respectively, in October 2013 and April 2017. The K-3 is a DSLR, while the A9 is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (K-3) and a full frame (A9) sensor. The Pentax has a resolution of 24.1 megapixels, whereas the Sony provides 24 MP.

Below is an overview of the main specs of the two cameras as a starting point for the comparison.

Headline Specifications
Pentax K-3   Sony A9
Pentax K-3 Sony A9
Digital single lens reflex Mirrorless system camera
Pentax K mount lenses Sony E mount lenses
24.1 MP, APS-C Sensor 24 MP, Full Frame Sensor
1080/60i Video 4K/30p Video
ISO 100-51200 ISO 100-51200 (50-204800)
Optical viewfinder Electronic viewfinder (3686k dots)
3.2" LCD, 1037k dots 3.0" LCD, 1440k dots
Fixed screen (not touch-sensitive) Tilting touchscreen
8.3 shutter flaps per second 20 shutter flaps per second
In-body stabilizationIn-body stabilization
Weathersealed bodyWeathersealed body
560 shots per battery charge650 shots per battery charge
131 x 100 x 77 mm, 800 g 127 x 96 x 63 mm, 673 g

Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax K-3 and the Sony Alpha A9? Which one should you buy? Read on to find out how these two cameras compare with respect to their body size, their imaging sensors, their shooting features, their input-output connections, and their reception by expert reviewers.

Body comparison: Pentax K-3 vs Sony A9

An illustration of the physical size and weight of the Pentax K-3 and the Sony A9 is provided 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 width, height and depth measures are rounded to the nearest millimeter.

The K-3 can be obtained in two different colors (black, silver), while the A9 is only available in black.

Size Pentax K-3 vs Sony A9
Compare K-3 versus A9 top
Comparison K-3 or A9 rear

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A9 is notably smaller (7 percent) than the Pentax K-3. Moreover, the A9 is markedly lighter (16 percent) than the K-3. 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 and compare 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-3 gets 560 shots out of its D-LI90 battery, while the A9 can take 650 images on a single charge of its NP-FZ100 power pack. The power pack in the A9 can be charged via the USB port, which can be very convenient when travelling.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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-3» 5.2 in 3.9 in 3.0 in 28.2 oz 560 Y Oct 2013 1,299- i Pentax K-3
 
Sony A9« 5.0 in 3.8 in 2.5 in 23.7 oz 650 Y Apr 2017 4,499 i i Sony A9
 
Canon 70D« » 5.5 in 4.1 in 3.1 in 26.6 oz 920 Y Jul 2013 1,199- i Canon 70D
 
Nikon Z6« » 5.3 in 4.0 in 2.6 in 23.8 oz 310 Y Aug 2018 1,999 i i Nikon Z6
 
Nikon D7200« » 5.4 in 4.2 in 3.0 in 27.0 oz 1110 Y Mar 2015 1,199- i Nikon D7200
 
Nikon D7100« » 5.4 in 4.2 in 3.0 in 27.0 oz 950 Y Feb 2013 1,199- i Nikon D7100
 
Panasonic GH5« » 5.5 in 3.9 in 3.4 in 25.6 oz 410 Y Jan 2017 1,999 i i Panasonic GH5
 
Pentax KP« » 5.2 in 4.0 in 3.0 in 24.8 oz 390 Y Jan 2017 1,099 i i Pentax KP
 
Pentax K-70« » 5.0 in 3.7 in 2.9 in 24.3 oz 410 Y Jun 2016 649 i i Pentax K-70
 
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
 
Pentax K-5« » 5.2 in 3.8 in 2.9 in 26.8 oz 740 Y Sep 2010 1,099- i Pentax K-5
 
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 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
 
Sony A6500« » 4.7 in 2.6 in 2.1 in 16.0 oz 350 Y Oct 2016 1,399 i i Sony A6500
 
Sony A7 II« » 5.0 in 3.8 in 2.4 in 21.1 oz 350 Y Nov 2014 1,999- i Sony A7 II
 
Sony A99« » 5.8 in 4.4 in 3.1 in 28.6 oz 500 Y Sep 2012 2,799- i Sony A99
 
Sony A77« » 5.6 in 4.1 in 3.2 in 25.8 oz 470 Y Aug 2011 1,399- i Sony A77
Note: Measurements and pricing do not include easily detachable parts, such as interchangeable lenses or optional viewfinders.

Any camera decision will obviously take relative prices into account. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The K-3 was launched at a markedly lower price (by 71 percent) than the A9, 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.

 

Sensor comparison: Pentax K-3 vs Sony A9

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. 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Pentax K-3 features an APS-C sensor and the Sony A9 a full frame sensor. The sensor area in the A9 is 131 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Pentax K-3 and Sony A9 sensor measures

Despite having a smaller sensor, the Pentax K-3 offers a higher resolution of 24.1 megapixels, compared with 24 MP of the Sony A9. This megapixels advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.90μm versus 5.94μm for the A9). Moreover, it should be noted that the A9 is much more recent (by 3 years and 6 months) than the K-3, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixel-units. Coming back to sensor resolution, it should be mentioned that the K-3 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The A9 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

The Pentax K-3 has a native sensitivity range from ISO 100 to ISO 51200. The corresponding ISO settings for the Sony Alpha A9 are ISO 100 to ISO 51200, with the possibility to increase the ISO range to 50-204800.

K-3 versus A9 MP

Consistent information on actual sensor performance is available from DXO Mark for many 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 A9 offers substantially better image quality than the K-3 (overall score 12 points higher). The advantage is based on 1.2 bits higher color depth, 0.1 EV of lower dynamic range, and 1.5 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
Model
Sensor
Class
Resolution
(MP)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Camera
Model
 
Pentax K-3» APS-C 24.1 6016 40001080/60i23.713.4121680Pentax K-3
 
Sony A9« Full Frame 24.0 6000 40004K/30p24.913.3351792Sony A9
 
Canon 70D« » APS-C 20.0 5472 36481080/30p22.511.692668Canon 70D
 
Nikon Z6« » Full Frame 24.3 6048 40244K/30p25.314.3329995Nikon Z6
 
Nikon D7200« » APS-C 24.0 6000 40001080/60p24.514.6133387Nikon D7200
 
Nikon D7100« » APS-C 24.0 6000 40001080/60p24.213.7125683Nikon D7100
 
Panasonic GH5« » Four Thirds 20.2 5184 38884K/60p23.913.080777Panasonic GH5
 
Pentax KP« » APS-C 24.1 6016 40001080/60i----Pentax KP
 
Pentax K-70« » APS-C 24.0 6000 40001080/60i----Pentax K-70
 
Pentax K-3 II« » APS-C 24.1 6016 40001080/60i23.613.6110680Pentax K-3 II
 
Pentax K-5« » APS-C 16.1 4928 32641080/25p23.714.1116282Pentax K-5
 
Sony A7 III« » Full Frame 24.0 6000 40004K/30p25.014.7373096Sony A7 III
 
Sony A7R III« » Full Frame 42.2 7952 53044K/30p26.014.73523100Sony A7R III
 
Sony A6500« » APS-C 24.0 6000 40004K/30p24.513.7140585Sony A6500
 
Sony A7 II« » Full Frame 24.0 6000 40001080/60p24.913.6244990Sony A7 II
 
Sony A99« » Full Frame 24.0 6000 40001080/60p25.014.0155589Sony A99
 
Sony A77« » APS-C 24.0 6000 40001080/60p24.013.280178Sony A77

Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the A9 provides a better video resolution than the K-3. It can shoot movie footage at 4K/30p, while the Pentax is limited to 1080/60i.

 

Feature comparison: Pentax K-3 vs Sony A9

Apart from body and sensor, cameras can and do differ across a range of features. For example, the A9 has an electronic viewfinder (3686k dots), while the K-3 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 viewfinders of both cameras offer the same field of view (100%), but the viewfinder of the A9 has a higher magnification than the one of the K-3 (0.78x vs 0.63x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The following table reports on some other key feature differences and similarities of the Pentax K-3, the Sony A9, and comparable cameras.

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)
Mech
Shutter
Speed
Shutter
Flaps
(1/sec)
Built-in
Flash
(yes/no)
Built-in
Image
Stab
Camera
Model
 
Pentax K-3»optical Y 3.2 1037 fixed n 1/8000s 8.3 Y Y Pentax K-3
 
Sony A9«3686 n 3.0 1440 tilting Y 1/8000s 20.0 n Y Sony A9
 
Canon 70D« »optical Y 3.0 1040 swivel Y 1/8000s 7.0 Y n Canon 70D
 
Nikon Z6« »3690 Y 3.2 2100 tilting Y 1/8000s 12.0 n Y Nikon Z6
 
Nikon D7200« »optical Y 3.2 1229 fixed n 1/8000s 6.0 Y n Nikon D7200
 
Nikon D7100« »optical Y 3.2 1229 fixed n 1/8000s 6.0 Y n Nikon D7100
 
Panasonic GH5« »3680 n 3.2 1620 swivel Y 1/8000s 12.0 n Y Panasonic GH5
 
Pentax KP« »optical n 3.0 921 tilting n 1/6000s 7.0 Y Y Pentax KP
 
Pentax K-70« »optical n 3.0 921 swivel n 1/6000s 6.0 Y Y Pentax K-70
 
Pentax K-3 II« »optical Y 3.2 1037 fixed n 1/8000s 8.3 n Y Pentax K-3 II
 
Pentax K-5« »optical Y 3.0 921 fixed n 1/8000s 7.0 Y Y Pentax K-5
 
Sony A7 III« »2359 n 3.0 922 tilting Y 1/8000s 10.0 n Y Sony A7 III
 
Sony A7R III« »3686 n 3.0 1440 tilting Y 1/8000s 10.0 n Y Sony A7R III
 
Sony A6500« »2359 n 3.0 922 tilting Y 1/4000s 11.0 Y Y Sony A6500
 
Sony A7 II« »2400 n 3.0 1230 tilting n 1/8000s 5.0 n Y Sony A7 II
 
Sony A99« »2359 Y 3.0 1229 full-flex n 1/8000s 6.0 n Y Sony A99
 
Sony A77« »2359 Y 3.0 921 full-flex n 1/8000s 12.0 Y Y Sony A77

One difference between the cameras concerns the presence of an on-board flash. The K-3 has one, while the A9 does not. While the built-in flash of the K-3 is not very powerful, it can at times be useful as a fill-in light.

The reported shutter speed information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, the A9 is one of those camera that have an additional electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).

The Pentax K-3 has an intervalometer built-in. This enables the photographer to capture time lapse sequences, such as flower blooming, a sunset or moon rise, without purchasing an external camera trigger and related software.

The K-3 writes its imaging data to SDXC cards, while the A9 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. The A9 supports UHS-II cards (on its first slot), while the K-3 can use UHS-I cards.

 

Connectivity comparison: Pentax K-3 vs Sony A9

For some imaging applications, the extent to which a camera can communicate with its environment can be an important aspect in the camera decision process. The table below provides an overview of the connectivity of the Pentax K-3 and Sony Alpha A9 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.

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-3»YmonomonoYYmini3.0---Pentax K-3
 
Sony A9«YstereomonoYYmicro2.0YYYSony A9
 
Canon 70D« »YstereomonoY-mini2.0Y--Canon 70D
 
Nikon Z6« »YstereomonoYYmicro3.1Y-YNikon Z6
 
Nikon D7200« »YstereomonoYYmini2.0YY-Nikon D7200
 
Nikon D7100« »YstereomonoYYmini2.0---Nikon D7100
 
Panasonic GH5« »YstereomonoYYfull3.1Y-YPanasonic GH5
 
Pentax KP« »YstereomonoY--2.0Y--Pentax KP
 
Pentax K-70« »YstereomonoY-mini2.0Y--Pentax K-70
 
Pentax K-3 II« »YmonomonoYYmini3.0---Pentax K-3 II
 
Pentax K-5« »YstereomonoY-mini2.0---Pentax K-5
 
Sony A7 III« »YstereomonoYYmicro3.1YYYSony A7 III
 
Sony A7R III« »YstereomonoYYmicro3.1YYYSony A7R III
 
Sony A6500« »YstereomonoY-micro2.0YY-Sony A6500
 
Sony A7 II« »YstereomonoYYmicro2.0YY-Sony A7 II
 
Sony A99« »YstereomonoYYmini2.0---Sony A99
 
Sony A77« »YstereomonoY-mini2.0---Sony A77

It is notable that the A9 offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the K-3 does not offer wifi capability.

Studio photographers will appreciate that the Pentax K-3 (unlike the A9) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

The A9 is a recent model that features in the current product line-up of Sony. In contrast, the K-3 has been discontinued (but it can be found pre-owned on eBay). As a replacement in the same line of cameras, the K-3 was succeeded by the Pentax K-3 II. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official Pentax and Sony websites.


Review summary: Pentax K-3 vs Sony A9

So how do things add up? Is the Pentax K-3 better than the Sony A9 or vice versa? Below is a summary of the relative strengths of each of the two contestants.

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Arguments in favor of the Pentax K-3:

  • Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
  • 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.
  • Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
  • Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
  • Faster data transfer: Supports a more advanced USB protocol (3.0 vs 2.0).
  • Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
  • More affordable: Was introduced into a lower priced category (71 percent cheaper at launch).
  • More heavily discounted: Has been available for much longer (launched in October 2013).

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Reasons to prefer the Sony Alpha A9:

  • Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
  • Better image quality: Scores substantially higher (12 points) in the DXO overall evaluation.
  • Richer colors: Generates noticeably more natural colors (1.2 bits more color depth).
  • Better low-light sensitivity: Can shoot in dim conditions (1.5 stops ISO advantage).
  • Better video: Provides higher definition movie capture (4K/30p vs 1080/60i).
  • Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
  • More framing info: Has an electronic viewfinder that displays shooting data.
  • Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.63x).
  • More detailed LCD: Has a higher resolution rear screen (1440k vs 1037k 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 burst: Shoots at higher frequency (20 vs 8.3 flaps/sec) to capture the decisive moment.
  • Less disturbing: Has an electronic shutter option for completely silent shooting.
  • Less heavy: Has a lower weight (by 127g or 16 percent) and is thus easier to take along.
  • Longer lasting: Gets more shots (650 versus 560) out of a single battery charge.
  • Easier travel charging: Can be conveniently charged via its USB port.
  • More legacy lens friendly: Can use many non-native lenses via adapters.
  • Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
  • Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
  • Easier wireless transfer: Supports Bluetooth for image sharing without cables.
  • Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
  • More modern: Reflects 3 years and 6 months of technical progress since the K-3 launch.

If the number of relative strengths (bullet points above) is taken as a guide, the A9 is the clear winner of the contest (21 : 10 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 before making a decision on a new camera. A professional wildlife photographer will view the differences between cameras in a way that diverges from the perspective of a family photog, and a person interested in architecture has distinct needs from a sports shooter. Hence, the decision which camera is best and worth buying is often a very personal one.

K-3 10:21 A9

How about other alternatives? Do the specifications of the Pentax K-3 and the Sony A9 place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Mirrorless Interchangeable Lens Camera listings whether the two cameras rank among the cream of the crop.

In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it says little about, for example, the shooting experience and imaging performance of the K-3 and the A9 in practical situations. 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.

Expert reviews: Pentax K-3 vs Sony A9

This is why hands-on reviews by experts are important. The table below provides a synthesis of the camera assessments of some of the best known photo-gear review sites (cameralabs, dpreview, ephotozine, imaging-resource, and photographyblog). As can be seen, the professional reviewers agree in many cases on the quality of different cameras, but sometimes their assessments diverge, reinforcing the earlier point that a camera decision is often a very personal choice.

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-3»-83/1005/54.5/55/5 Oct 2013 1,299- i Pentax K-3
 
Sony A9«+ +89/1005/55/55/5 Apr 2017 4,499 i i Sony A9
 
Canon 70D« »+ +83/1004.5/54.5/55/5 Jul 2013 1,199- i Canon 70D
 
Nikon Z6« »--4.5/5-5/5 Aug 2018 1,999 i i Nikon Z6
 
Nikon D7200« »+ +84/1004.5/54/54.5/5 Mar 2015 1,199- i Nikon D7200
 
Nikon D7100« »+ +85/1004.5/55/54.5/5 Feb 2013 1,199- i Nikon D7100
 
Panasonic GH5« »+ +85/1004.5/55/55/5 Jan 2017 1,999 i i Panasonic GH5
 
Pentax KP« »-82/1005/5-4.5/5 Jan 2017 1,099 i i Pentax KP
 
Pentax K-70« »-79/1004.5/54/54.5/5 Jun 2016 649 i i Pentax K-70
 
Pentax K-3 II« »--5/54.5/55/5 Apr 2015 1,099 i i Pentax K-3 II
 
Pentax K-5« »-83/1005/54.5/54.5/5 Sep 2010 1,099- i Pentax K-5
 
Sony A7 III« »+ +89/1005/55/55/5 Feb 2018 1,999 i i Sony A7 III
 
Sony A7R III« »+ +90/1004.5/55/55/5 Oct 2017 3,199 i i Sony A7R III
 
Sony A6500« »+ +85/1004.5/55/54.5/5 Oct 2016 1,399 i i Sony A6500
 
Sony A7 II« »+82/1004.5/55/55/5 Nov 2014 1,999- i Sony A7 II
 
Sony A99« »-84/1004.5/5o4.5/5 Sep 2012 2,799- i Sony A99
 
Sony A77« »91/10081/100-4.5/55/5 Aug 2011 1,399- i Sony A77
Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (-) not available.

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. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, 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.

Pentax K-3:
Check Ebay offers
Sony A9:
Check Amazon price

Other camera comparisons

Did this review help to inform your camera decision process? In case you would like to check on the differences and similarities of other camera models, just make your choice using the following search menu. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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    Specifications: Pentax K-3 vs Sony A9

    Below is a side-by-side comparison of the specs of the two cameras to facilitate a quick review of their differences and common features.

    Camera Specifications
    Camera Model Pentax K-3 Sony A9
    Camera Type Digital single lens reflex Mirrorless system camera
    Camera Lens Pentax K mount lenses Sony E mount lenses
    Launch Date October 2013 April 2017
    Launch Price USD 1299 USD 4499
    Sensor Specs Pentax K-3 Sony A9
    Sensor Technology CMOS BSI-CMOS
    Sensor Format APS-C Sensor Full Frame Sensor
    Sensor Size 23.5 x 15.6 mm 35.6 x 23.8 mm
    Sensor Area 366.6 mm2 847.28 mm2
    Sensor Diagonal 28.2 mm 42.8 mm
    Crop Factor 1.5x 1.0x
    Sensor Resolution 24.1 Megapixels 24 Megapixels
    Image Resolution 6016 x 4000 pixels 6000 x 4000 pixels
    Pixel Pitch 3.90 μm 5.94 μm
    Pixel Density 6.56 MP/cm2 2.83 MP/cm2
    Moiré control no AA filter Anti-Alias filter
    Movie Capability 1080/60i Video 4K/30p Video
    ISO Setting 100-51200 ISO 100-51200 ISO
    ISO Boost no Enhancement 50-204800 ISO
    Image Processor PRIME III BIONZ X
    DXO Sensor Quality (score) 80 92
    DXO Color Depth (bits) 23.7 24.9
    DXO Dynamic Range (EV) 13.4 13.3
    DXO Low Light (ISO) 1216 3517
    Screen Specs Pentax K-3 Sony A9
    Viewfinder Type Optical viewfinder Electronic viewfinder
    Viewfinder Field of View 100% 100%
    Viewfinder Magnification 0.63x 0.78x
    Viewfinder Resolution 3686k dots
    Top-Level Screen Control Panel no Top Display
    LCD Framing Live View Live View
    Rear LCD Size 3.2 inch 3.0 inch
    LCD Resolution 1037k dots 1440k dots
    LCD Attachment Fixed screen Tilting screen
    Touch Input no Touchscreen Touchscreen
    Shooting Specs Pentax K-3 Sony A9
    Autofocus System Phase-detect AF On-Sensor Phase-detect
    Manual Focusing AidFocus PeakingFocus Peaking
    Max Shutter Speed (mechanical) 1/8000/s 1/8000/s
    Continuous Shooting 8.3 shutter flaps/s 20 shutter flaps/s
    Shutter Life Expectancy200 000 actuations500 000 actuations
    Electronic Shutterno E-Shutterup to 1/32000s
    Time-Lapse PhotographyIntervalometer built-inno Intervalometer
    Image StabilizationIn-body stabilizationIn-body stabilization
    Fill Flash Build-in Flash no On-Board Flash
    Storage Medium SDXC cards MS or SDXC cards
    Second Storage Option Dual card slots Dual card slots
    UHS card support UHS-I Single UHS-II
    Connectivity Specs Pentax K-3 Sony A9
    External Flash Hotshoe Hotshoe
    Studio Flash PC Sync socket no PC Sync
    USB Connector USB 3.0 USB 2.0
    HDMI Port mini HDMI micro HDMI
    Microphone Port External MIC port External MIC port
    Headphone Socket Headphone port Headphone port
    Wifi Support no Wifi Wifi built-in
    Near-Field Communication no NFC NFC built-in
    Bluetooth Support no Bluetooth Bluetooth built-in
    Body Specs Pentax K-3 Sony A9
    Environmental SealingWeathersealed bodyWeathersealed body
    Battery Type D-LI90 power pack NP-FZ100 power pack
    Battery Life (CIPA)560 shots per charge650 shots per charge
    In-Camera Charging no USB charging USB charging
    Body Dimensions 131 x 100 x 77 mm
    (5.2 x 3.9 x 3.0 in)
    127 x 96 x 63 mm
    (5.0 x 3.8 x 2.5 in)
    Camera Weight 800 g (28.2 oz) 673 g (23.7 oz)

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