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Pentax K-3 versus Sony RX10

The Pentax K-3 and the Sony Cyber-shot DSC-RX10 are two enthusiast cameras that were officially introduced in October 2013. The K-3 is a DSLR, while the RX10 is a fixed lens compact. The cameras are based on an APS-C (K-3) and an one-inch (RX10) sensor. The Pentax has a resolution of 24.1 megapixel, whereas the Sony provides 20 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-3 vs Sony RX10

The physical size and weight of the Pentax K-3 and the Sony RX10 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 width, height and depth measures are rounded to the nearest millimeter. You can also use the toggle button to switch to a percentage comparison if you prefer that the measures are being expressed in relative terms (in this case, the camera on the left – the K-3 – represents the basis or 100 percent across all the size and weight measures).

Compare Pentax K-3 vs Sony RX10
Compare K-3 versus RX10 top
Compare K-3 and RX10 rear

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony RX10 is notably smaller (13 percent) than the Pentax 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 and possibly misleading, as the RX10 has a lens build in, whereas the K-3 is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup.

Concerning battery life, the K-3 gets 560 shots out of its D-LI90 battery, while the RX10 can take 420 images on a single charge of its NP-FW50 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-3» 5.2 in 3.9 in 3.0 in 28.2 oz 560 Y Oct 2013 1,299- i Pentax K-3
Sony RX10« 5.1 in 3.5 in 4.0 in 28.7 oz 420 Y Oct 2013 1,299- i Sony RX10
Canon 7D II« » 5.9 in 4.4 in 3.1 in 32.1 oz 670 Y Sep 2014 1,799 i i Canon 7D II
Canon 70D« » 5.5 in 4.1 in 3.1 in 26.6 oz 920 Y Jul 2013 1,199- i Canon 70D
Nikon D7100« » 5.4 in 4.2 in 3.0 in 27.0 oz 950 Y Feb 2013 1,199- i Nikon D7100
Olympus E-M1« » 5.1 in 3.7 in 2.5 in 17.5 oz 350 Y Sep 2013 1,399- i Olympus E-M1
Panasonic GX8« » 5.2 in 3.1 in 2.5 in 17.2 oz 330 Y Jul 2015 1,199- i Panasonic GX8
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 RX10 III« » 5.2 in 3.7 in 5.0 in 37.1 oz 420 Y Mar 2016 1,499- i Sony RX10 III
Sony RX10 II« » 5.1 in 3.5 in 4.0 in 28.7 oz 400 Y Jun 2015 1,299- i Sony RX10 II
Sony A99« » 5.8 in 4.4 in 3.1 in 28.6 oz 500 Y Sep 2012 2,799- i Sony A99

The camera’s price is obviously a critical decision-making factor. The manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. 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 RX10

The size of the imaging sensor is a crucial determinant 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 more expensive and 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 RX10 an one-inch sensor. The sensor area in the RX10 is 68 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 2.7. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Pentax K-3 and Sony RX10 sensor measures

With 24.1MP, the K-3 offers a higher resolution than the RX10 (20MP), but the K-3 nevertheless has larger individual pixels (pixel pitch of 3.90μm versus 2.41μm for the RX10) due to its larger sensor. It is noteworthy in this context that the two cameras were released in close succession, so that their sensors are from the same technological generation. 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.

K-3 versus RX10 MP

For many 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"). Of the two cameras under review, the K-3 provides substantially higher image quality than the RX10, with an overall score that is 11 points higher. This advantage is based on 0.8 bits higher color depth, 0.8 EV in additional dynamic range, and 1.4 stops in additional low light sensitivity. The table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar 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 RX10« 1-inch 20.0 5472 36481080/60p22.912.647469Sony RX10
Canon 7D II« » APS-C 20.0 5472 36481080/60p22.411.8108270Canon 7D II
Canon 70D« » APS-C 20.0 5472 36481080/30p22.511.692668Canon 70D
Nikon D7100« » APS-C 24.0 6000 40001080/60p24.213.7125683Nikon D7100
Olympus E-M1« » Four Thirds 15.9 4608 34561080/30p23.012.775773Olympus E-M1
Panasonic GX8« » Four Thirds 20.2 5184 38884K/30p23.512.680675Panasonic GX8
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 RX10 III« » 1-inch 20.0 5472 36484K/30p23.112.647270Sony RX10 III
Sony RX10 II« » 1-inch 20.0 5472 36484K/30p23.012.653170Sony RX10 II
Sony A99« » Full Frame 24.0 6000 40001080/60p25.014.0155589Sony A99

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 RX10 provides a faster frame rate than the K-3. It can shoot movie footage at 1080/60p, while the Pentax is limited to 1080/60i.

 

Feature comparison: Pentax K-3 vs Sony RX10

Beyond body and sensor, cameras can and do differ across a range of features. For example, the RX10 has an electronic viewfinder (1440k 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 table below summarizes some of the other core capabilities of the Pentax K-3 and Sony RX10 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-3»optical Y 3.2 1037 fixed n 8000 8.3 Y Y Pentax K-3
Sony RX10«1440 Y 3.0 1229 tilting n 3200 10.0 Y Y Sony RX10
Canon 7D II« »optical Y 3.0 1040 fixed n 8000 10.0 Y n Canon 7D II
Canon 70D« »optical Y 3.0 1040 swivel Y 8000 7.0 Y n Canon 70D
Nikon D7100« »optical Y 3.2 1229 fixed n 8000 6.0 Y n Nikon D7100
Olympus E-M1« »2360 n 3.0 1037 tilting Y 8000 10.0 n Y Olympus E-M1
Panasonic GX8« »2360 n 3.0 1040 swivel Y 8000 10.0 n Y Panasonic GX8
Pentax KP« »optical n 3.0 921 tilting n 6000 7.0 Y Y Pentax KP
Pentax K-70« »optical n 3.0 921 swivel n 6000 6.0 Y Y Pentax K-70
Pentax K-3 II« »optical Y 3.2 1037 fixed n 8000 8.3 n Y Pentax K-3 II
Pentax K-5« »optical Y 3.0 921 fixed n 8000 7.0 Y Y Pentax K-5
Sony RX10 III« »2359 Y 3.0 1229 tilting n 2000 14.0 Y Y Sony RX10 III
Sony RX10 II« »2359 Y 3.0 1229 tilting n 3200 14.0 Y Y Sony RX10 II
Sony A99« »2359 Y 3.0 1229 full-flex n 8000 6.0 n Y Sony A99

Both the K-3 and the RX10 have been discontinued, but can regularly be found used on eBay. The K-3 was replaced by the Pentax K-3 II, while the RX10 was followed by the Sony RX10 II.

Review summary: Pentax K-3 vs Sony RX10

So what is the bottom line? Which of the two cameras – the Pentax K-3 or the Sony RX10 – has the upper hand? The listing below highlights the relative strengths of the two models.

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Reasons to prefer the Pentax K-3:

  • More detail: Offers more megapixels (24.1 vs 20MP) with a 10% higher linear resolution.
  • Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
  • Better image quality: Scores substantially higher (11 points) in the DXO overall assessment.
  • More dynamic range: Captures a larger spectrum of light and dark details (0.8 EV of extra DR).
  • Better low-light sensitivity: Requires less light for good images (1.4 stops ISO advantage).
  • Brighter framing: Features an optical viewfinder for clear, lag-free composition.
  • Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
  • Faster shutter: Has higher mechanical shutter speed (8000/sec vs 3200/sec) to freeze action.
  • More flexible: Can take a variety of interchangeable lenses, including specialty optics.
  • Longer lasting: Can take more shots (560 versus 420) on a single battery charge.

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Advantages of the Sony Cyber-shot DSC-RX10:

  • Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
  • Better video: Provides higher movie framerates (1080/60p versus 1080/60i).
  • More framing info: Has an electronic viewfinder that displays shooting data.
  • More detailed LCD: Has a higher resolution rear screen (1229k vs 1037k dots).
  • More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
  • Faster burst: Shoots at higher frequency (10 vs 8.3 flaps/sec) to capture the decisive moment.
  • Ready to shoot: Comes with an integrated lens, while the K-3 requires a separate lens.
  • More compact: Is smaller (129x88mm vs 131x100mm) and will fit more readily into a bag.

If the number of relative strengths (bullet points above) is taken as a guide, the K-3 emerges as the winner of the contest (10 : 8 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.

K-3 10:08 RX10

In any case, while the specs-based evaluation of cameras is instructive in revealing their potential as photographic tools, it remains incomplete and does no justice, for example, to the way the K-3 or the RX10 handle or perform in practice. User reviews, such as those found at amazon, can sometimes inform about these issues, but such feedback is often incomplete, inconsistent, and biased. This is why expert reviews are important. The following table reports the overall rankings of the cameras as published by some of the major camera review sites (cameralabs, dpreview, ephotozine, imaging-resource, photographyblog). The detailed reviews can be accessed 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-3»-83/1005/54.5/55/5 Oct 2013 1,299- i Pentax K-3
Sony RX10«Rec80/1004.5/54.5/54.5/5 Oct 2013 1,299- i Sony RX10
Canon 7D II« »Rec84/1004/55/54.5/5 Sep 2014 1,799 i i Canon 7D II
Canon 70D« »HiRec83/1004.5/54.5/55/5 Jul 2013 1,199- i Canon 70D
Nikon D7100« »HiRec85/1004.5/55/54.5/5 Feb 2013 1,199- i Nikon D7100
Olympus E-M1« »HiRec84/1004.5/54.5/54.5/5 Sep 2013 1,399- i Olympus E-M1
Panasonic GX8« »Rec82/1004.5/55/54.5/5 Jul 2015 1,199- i Panasonic GX8
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 RX10 III« »Rec84/1004.5/54.5/54.5/5 Mar 2016 1,499- i Sony RX10 III
Sony RX10 II« »HiRec82/1004.5/54.5/54/5 Jun 2015 1,299- i Sony RX10 II
Sony A99« »-84/1004.5/5rev4.5/5 Sep 2012 2,799- i Sony A99

Care should be taken when interpreting the review scores above, 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 rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

 

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. If the camera you are interested in is not available, kindly get in touch, and I will try to update the database with the necessary infos.

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