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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. Three consecutive perspectives from the front, the top, and the back are presented. All width, height and depth dimensions are rounded to the nearest millimeter. You can also toggle the display 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
K-3 versus RX10 top view
K-3 and RX10 rear side
Body view (K-3 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 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. 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 camera 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-3 (⇒ rgt) 131 mm 100 mm 77 mm 800 g 560 YES 2013 1,299discont. check
Sony RX10 (⇒ lft) 129 mm 88 mm 102 mm 813 g 420 YES 2013 1,299discont. check
Canon 7D II (⇒ lft | rgt) 149 mm 112 mm 78 mm 910 g 670 YES 2014 1,799 latest check
Canon 70D (⇒ lft | rgt) 139 mm 104 mm 79 mm 755 g 920 YES 2013 1,199discont. check
Nikon D7100 (⇒ lft | rgt) 136 mm 107 mm 76 mm 765 g 950 YES 2013 1,199discont. check
Olympus E-M1 (⇒ lft | rgt) 130 mm 94 mm 63 mm 497 g 350 YES 2013 1,399discont. check
Panasonic GX8 (⇒ lft | rgt) 133 mm 78 mm 63 mm 487 g 330 YES 2015 1,199discont. check
Pentax KP (⇒ lft | rgt) 132 mm 101 mm 76 mm 703 g 390 YES 2017 1,099 latest check
Pentax K-70 (⇒ lft | rgt) 126 mm 93 mm 74 mm 688 g 410 YES 2016 649 latest check
Pentax K-3 II (⇒ lft | rgt) 131 mm 100 mm 77 mm 800 g 720 YES 2015 1,099 latest check
Pentax K-5 (⇒ lft | rgt) 131 mm 97 mm 73 mm 760 g 740 YES 2010 1,099discont. check
Sony RX10 III (⇒ lft | rgt) 133 mm 94 mm 127 mm 1051 g 420 YES 2016 1,499discont. check
Sony RX10 II (⇒ lft | rgt) 129 mm 88 mm 102 mm 813 g 400 YES 2015 1,299discont. check
Sony A99 (⇒ lft | rgt) 147 mm 111 mm 78 mm 812 g 500 YES 2012 2,799discont. check

The price is, of course, an important factor in any camera decision. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. 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: Pentax K-3 vs Sony RX10

The size of the imaging sensor is a crucial determinant 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 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
Sensor size

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
Sensor resolution

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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 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 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-3 (⇒ rgt) APS-C 24.1 6016 4000 1080/60i 23.7 13.4 1216 80
Sony RX10 (⇒ lft) 1-inch 20.0 5472 3648 1080/60p 22.9 12.6 474 69
Canon 7D II (⇒ lft | rgt) APS-C 20.0 5472 3648 1080/60p 22.4 11.8 1082 70
Canon 70D (⇒ lft | rgt) APS-C 20.0 5472 3648 1080/30p 22.5 11.6 926 68
Nikon D7100 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p 24.2 13.7 1256 83
Olympus E-M1 (⇒ lft | rgt) Four Thirds 15.9 4608 3456 1080/30p 23.0 12.7 757 73
Panasonic GX8 (⇒ lft | rgt) Four Thirds 20.2 5184 3888 4K/30p 23.5 12.6 806 75
Pentax KP (⇒ lft | rgt) APS-C 24.1 6016 4000 1080/60i - - - -
Pentax K-70 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60i - - - -
Pentax K-3 II (⇒ lft | rgt) APS-C 24.1 6016 4000 1080/60i 23.6 13.6 1106 80
Pentax K-5 (⇒ lft | rgt) APS-C 16.1 4928 3264 1080/25p 23.7 14.1 1162 82
Sony RX10 III (⇒ lft | rgt) 1-inch 20.0 5472 3648 4K/30p 23.1 12.6 472 70
Sony RX10 II (⇒ lft | rgt) 1-inch 20.0 5472 3648 4K/30p 23.0 12.6 531 70
Sony A99 (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 25.0 14.0 1555 89

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 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

Apart from body and sensor, cameras can and do differ across a variety 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 adjacent table lists some of the other core features of the Pentax K-3 and Sony RX10 along with similar information for a selection of comparators. 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-3 (⇒ rgt) optical YES 3.2 1037 fixed no 8000 8.3 13 YES
Sony RX10 (⇒ lft) 1440 YES 3.0 1229 tilting no 3200 10.0 10.2 YES
Canon 7D II (⇒ lft | rgt) optical YES 3.0 1040 fixed no 8000 10.0 11 no
Canon 70D (⇒ lft | rgt) optical YES 3.0 1040 swivel YES 8000 7.0 12 no
Nikon D7100 (⇒ lft | rgt) optical YES 3.2 1229 fixed no 8000 6.0 12 no
Olympus E-M1 (⇒ lft | rgt) 2360 no 3.0 1037 tilting YES 8000 10.0 no YES
Panasonic GX8 (⇒ lft | rgt) 2360 no 3.0 1040 swivel YES 8000 10.0 no YES
Pentax KP (⇒ lft | rgt) optical no 3.0 921 tilting no 6000 7.0 YES YES
Pentax K-70 (⇒ lft | rgt) optical no 3.0 921 swivel no 6000 6.0 YES YES
Pentax K-3 II (⇒ lft | rgt) optical YES 3.2 1037 fixed no 8000 8.3 no YES
Pentax K-5 (⇒ lft | rgt) optical YES 3.0 921 fixed no 8000 7.0 13 YES
Sony RX10 III (⇒ lft | rgt) 2359 YES 3.0 1229 tilting no 2000 14.0 10.8 YES
Sony RX10 II (⇒ lft | rgt) 2359 YES 3.0 1229 tilting no 3200 14.0 10.2 YES
Sony A99 (⇒ lft | rgt) 2359 YES 3.0 1229 full-flex no 8000 6.0 no YES

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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Advantages of 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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Arguments in favor 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 count of relative strengths (bullet points above) is taken as a measure, the K-3 emerges as the winner of the contest (10 : 8 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-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 partial and cannot reveal, for example, the handling experience and imaging performance when actually working with the K-3 or the RX10. 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 where reviews by experts come in. The following table reports the overall rankings of the cameras as published by some of the major 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
.com
dp
review
.com
ephoto
zine
.com
imaging
resource
.com
photography
blog
.com
Camera
Launch
(year)
Launch
Price
(USD)
Street
Price
(amazon)
Used
Price
(ebay)
Pentax K-3 (⇒ rgt) - 83/100 Gold 5/5 4.5/5 5/5 2013 1,299discont. check
Sony RX10 (⇒ lft) Rec 80/100 Gold 4.5/5 4.5/5 4.5/5 2013 1,299discont. check
Canon 7D II (⇒ lft | rgt) Rec 84/100 Silver 4/5 5/5 4.5/5 2014 1,799 latest check
Canon 70D (⇒ lft | rgt) HiRec 83/100 Gold 4.5/5 4.5/5 5/5 2013 1,199discont. check
Nikon D7100 (⇒ lft | rgt) HiRec 85/100 Gold 4.5/5 5/5 4.5/5 2013 1,199discont. check
Olympus E-M1 (⇒ lft | rgt) HiRec 84/100 Gold 4.5/5 4.5/5 4.5/5 2013 1,399discont. check
Panasonic GX8 (⇒ lft | rgt) Rec 82/100 Silver 4.5/5 5/5 4.5/5 2015 1,199discont. check
Pentax KP (⇒ lft | rgt) - 82/100 Silver 5/5 - 4.5/5 2017 1,099 latest check
Pentax K-70 (⇒ lft | rgt) - 79/100 Silver 4.5/5 4/5 4.5/5 2016 649 latest check
Pentax K-3 II (⇒ lft | rgt) - - 5/5 4.5/5 5/5 2015 1,099 latest check
Pentax K-5 (⇒ lft | rgt) - 83/100 Gold 5/5 4.5/5 4.5/5 2010 1,099discont. check
Sony RX10 III (⇒ lft | rgt) Rec 84/100 Silver 4.5/5 4.5/5 4.5/5 2016 1,499discont. check
Sony RX10 II (⇒ lft | rgt) HiRec 82/100 Gold 4.5/5 4.5/5 4/5 2015 1,299discont. check
Sony A99 (⇒ lft | rgt) - 84/100 Gold 4.5/5 reviewed 4.5/5 2012 2,799discont. check

The above review scores should be interpreted with care, though. The assessments were made in relation to similar cameras of the same technological generation. 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. Also, please note that some of the review sites have changed their methodology and reporting over time.


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 use the search menu below. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting. If the camera you are interested in is not available, please contact me, and I will try to locate and add the respective data to the application.

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