Pentax K-3 vs Sony RX100 III
The Pentax K-3 and the Sony Cyber-shot DSC-RX100 III are two digital cameras that were revealed to the public, respectively, in October 2013 and May 2014. The K-3 is a DSLR, while the RX100 III is a fixed lens compact. The cameras are based on an APS-C (K-3) and an one-inch (RX100 III) sensor. The Pentax has a resolution of 24.1 megapixels, whereas the Sony provides 20 MP.
Below is an overview of the main specs of the two cameras as a starting point for the comparison.
Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax K-3 and the Sony Cyber-shot DSC-RX100 III? 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.
An illustration of the physical size and weight of the Pentax K-3 and the Sony RX100 III is provided in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All size dimensions are rounded to the nearest millimeter.
The K-3 can be obtained in two different colors (black, silver), while the RX100 III is only available in black.
If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony RX100 III is considerably smaller (55 percent) than the Pentax K-3. It is worth mentioning in this context that the K-3 is splash and dust resistant, while the RX100 III does not feature any corresponding weather-sealing.
The above size and weight comparisons are to some extent incomplete and possibly misleading, as the RX100 III has a lens built 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 RX100 III can take 320 images on a single charge of its NP-BX1 power pack. The power pack in the RX100 III can be charged via the USB port, which can be very convenient when travelling.
The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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.
|Pentax K-3||5.2 in||3.9 in||3.0 in||28.2 oz||560||Y||Oct 2013||1,299|
|Sony RX100 III||4.0 in||2.3 in||1.6 in||10.2 oz||320||n||May 2014||799|
|Canon G7 X||4.1 in||2.4 in||1.6 in||10.7 oz||210||n||Sep 2014||699|
|Canon 70D||5.5 in||4.1 in||3.1 in||26.6 oz||920||Y||Jul 2013||1,199|
|Nikon D7200||5.4 in||4.2 in||3.0 in||27.0 oz||1110||Y||Mar 2015||1,199|
|Nikon D7100||5.4 in||4.2 in||3.0 in||27.0 oz||950||Y||Feb 2013||1,199|
|Pentax KP||5.2 in||4.0 in||3.0 in||24.8 oz||390||Y||Jan 2017||1,099|
|Pentax K-70||5.0 in||3.7 in||2.9 in||24.3 oz||410||Y||Jun 2016||649|
|Pentax K-3 II||5.2 in||3.9 in||3.0 in||28.2 oz||720||Y||Apr 2015||1,099|
|Pentax K-5||5.2 in||3.8 in||2.9 in||26.8 oz||740||Y||Sep 2010||1,099|
|Sony RX100 VII||4.0 in||2.3 in||1.7 in||10.7 oz||260||n||Jul 2019||1,199|
|Sony A6500||4.7 in||2.6 in||2.1 in||16.0 oz||350||Y||Oct 2016||1,399|
|Sony RX100 IV||4.0 in||2.3 in||1.6 in||10.5 oz||280||n||Jun 2015||999|
|Sony RX100 II||4.0 in||2.3 in||1.5 in||9.9 oz||350||n||Jun 2013||749|
|Sony A99||5.8 in||4.4 in||3.1 in||28.6 oz||500||Y||Sep 2012||2,799|
|Sony RX100||4.0 in||2.3 in||1.4 in||8.5 oz||330||n||Jun 2012||649|
|Sony A77||5.6 in||4.1 in||3.2 in||25.8 oz||470||Y||Aug 2011||1,399|
Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
(1) Number of images that can be taken on a full battery charge according to the CIPA-standard; (2) Official announcement.
Any camera decision will naturally be influenced heavily by the price. The manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The RX100 III was launched at a lower price than the K-3, despite having a lens built in. 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.
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 RX100 III an one-inch sensor. The sensor area in the RX100 III 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.
With 24.1MP, the K-3 offers a higher resolution than the RX100 III (20MP), but the K-3 nevertheless has larger individual pixels (pixel pitch of 3.90μm versus 2.41μm for the RX100 III) due to its larger sensor. However, the RX100 III is a somewhat more recent model (by 7 months) than the K-3, and its sensor might have benefitted from technological advances during this time that enhance the light gathering capacity of its pixels. 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 resolution advantage of the Pentax K-3 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the K-3 for good quality output (200 dots per inch) amounts to 30.1 x 20 inches or 76.4 x 50.8 cm, for very good quality (250 dpi) 24.1 x 16 inches or 61.1 x 40.6 cm, and for excellent quality (300 dpi) 20.1 x 13.3 inches or 50.9 x 33.9 cm. The corresponding values for the Sony RX100 III are 27.4 x 18.2 inches or 69.5 x 46.3 cm for good quality, 21.9 x 14.6 inches or 55.6 x 37.1 cm for very good quality, and 18.2 x 12.2 inches or 46.3 x 30.9 cm for excellent quality prints.
The Pentax K-3 has a native sensitivity range from ISO 100 to ISO 51200. The corresponding ISO settings for the Sony Cyber-shot DSC-RX100 III are ISO 100 to ISO 12800, with the possibility to increase the ISO range to 80-25600.
Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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 review, the K-3 provides substantially higher image quality than the RX100 III, with an overall score that is 13 points higher. This advantage is based on 1.3 bits higher color depth, 1.1 EV in additional dynamic range, and 1.3 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.
|Sony RX100 III||1-inch||20.0||5472||3648||1080/60p||22.4||12.3||495||67|
|Canon G7 X||1-inch||20.0||5472||3648||1080/60p||23.0||12.7||556||71|
|Pentax K-3 II||APS-C||24.1||6016||4000||1080/60i||23.6||13.6||1106||80|
|Sony RX100 VII||1-inch||20.0||5472||3648||4K/30p||21.8||12.4||418||63|
|Sony RX100 IV||1-inch||20.0||5472||3648||4K/30p||22.8||12.6||591||70|
|Sony RX100 II||1-inch||20.0||5472||3648||1080/60p||22.5||12.4||483||67|
|Sony A99||Full Frame||24.0||6000||4000||1080/60p||25.0||14.0||1555||89|
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 RX100 III 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.
Beyond body and sensor, cameras can and do differ across a range of features. For example, the RX100 III 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 viewfinders of both cameras offer the same field of view (100%), but the viewfinder of the K-3 has a higher magnification than the one of the RX100 III (0.63x vs 0.22x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The table below summarizes some of the other core capabilities of the Pentax K-3 and Sony RX100 III in connection with corresponding information for a sample of similar cameras.
|Sony RX100 III||1440||n||3.0||1229||tilting||n||1/2000s||10.0||Y||Y|
|Canon G7 X||none||n||3.0||1040||tilting||Y||1/2000s||6.5||Y||Y|
|Pentax K-3 II||optical||Y||3.2||1037||fixed||n||1/8000s||8.3||n||Y|
|Sony RX100 VII||2359||n||3.0||921||tilting||Y||1/2000s||90.0||Y||Y|
|Sony RX100 IV||2359||n||3.0||1228||tilting||n||1/2000s||16.0||Y||Y|
|Sony RX100 II||optional||n||3.0||1229||tilting||n||1/2000s||10.0||Y||Y|
One feature that is present on the K-3, but is missing on the RX100 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 RX100 III has an articulated screen that can be turned to be front-facing. This characteristic will be appreciated by vloggers and photographers who are interested in taking selfies. In contrast, the K-3 does not have a selfie-screen.
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 RX100 III uses SDXC or Memory Stick PRO Duo cards. The K-3 features dual card slots, which can be very useful in case a memory card fails. In contrast, the RX100 III only has one slot. Both cameras can use UHS-I cards, which provide for Ultra High Speed data transfer of up to 104 MB/s.
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 Cyber-shot DSC-RX100 III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
|Sony RX100 III||-||stereo||mono||-||-||micro||2.0||Y||Y||-|
|Canon G7 X||-||stereo||mono||-||-||micro||2.0||Y||Y||-|
|Pentax K-3 II||Y||mono||mono||Y||Y||mini||3.0||-||-||-|
|Sony RX100 VII||-||stereo||mono||Y||-||micro||2.0||Y||Y||Y|
|Sony RX100 IV||-||stereo||mono||-||-||micro||2.0||Y||Y||-|
|Sony RX100 II||Y||stereo||mono||-||-||micro||2.0||Y||Y||-|
It is notable that the K-3 has a hotshoe, while the RX100 III does not. This socket makes it possible to easily attach optional accessories, such as an external flash gun.
Studio photographers will appreciate that the Pentax K-3 (unlike the RX100 III) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Both the K-3 and the RX100 III have been discontinued, but can regularly be found used on eBay. The K-3 was replaced by the Pentax K-3 II, while the RX100 III was followed by the Sony RX100 IV. 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.
So how do things add up? Is there a clear favorite between the Pentax K-3 and the Sony RX100 III? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.
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 (13 points) in the DXO overall assessment.
- Richer colors: Generates images with noticeably better colors (1.3 bits more color depth).
- More dynamic range: Captures a larger spectrum of light and dark details (1.1 EV of extra DR).
- Better low-light sensitivity: Requires less light for good images (1.3 stops ISO advantage).
- Better sound: Can connect to an external microphone for higher quality sound recording.
- Better sound control: Has a headphone port that enables audio monitoring while recording.
- Brighter framing: Features an optical viewfinder for clear, lag-free composition.
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.63x vs 0.22x).
- 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.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/2000s) to freeze action.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- More flexible: Can take a variety of interchangeable lenses, including specialty optics.
- Longer lasting: Can take more shots (560 versus 320) on a single battery charge.
- Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
- Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
- 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.
- Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
- More heavily discounted: Has been on the market for longer (launched in October 2013).
Reasons to prefer the Sony Cyber-shot DSC-RX100 III:
- 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.
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- 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 (102x58mm vs 131x100mm) and will fit more readily into a bag.
- Less heavy: Has a lower weight even though it has a lens built in (unlike the K-3).
- Easier travel charging: Can be conveniently charged via its USB port.
- 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.
- More affordable: Was introduced at a lower price, despite coming with a built-in lens.
- More modern: Was introduced somewhat (7 months) more recently.
If the count of relative strengths (bullet points above) is taken as a measure, the K-3 is the clear winner of the match-up (22 : 15 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.
How about other alternatives? Do the specifications of the Pentax K-3 and the Sony RX100 III place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Travel-Zoom 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 RX100 III in practical situations. 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 ratings of the cameras as published by some of the major camera 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.
|Pentax K-3||..||83/100||5/5||4.5/5||5/5||Oct 2013||1,299|
|Sony RX100 III||+ +||82/100||4.5/5||4.5/5||5/5||May 2014||799|
|Canon G7 X||+ +||77/100||4.5/5||3.5/5||4.5/5||Sep 2014||699|
|Canon 70D||+ +||83/100||4.5/5||4.5/5||5/5||Jul 2013||1,199|
|Nikon D7200||+ +||84/100||4.5/5||4/5||4.5/5||Mar 2015||1,199|
|Nikon D7100||+ +||85/100||4.5/5||5/5||4.5/5||Feb 2013||1,199|
|Pentax KP||..||82/100||5/5||..||4.5/5||Jan 2017||1,099|
|Pentax K-70||..||79/100||4.5/5||4/5||4.5/5||Jun 2016||649|
|Pentax K-3 II||..||..||5/5||4.5/5||5/5||Apr 2015||1,099|
|Pentax K-5||..||83/100||5/5||4.5/5||4.5/5||Sep 2010||1,099|
|Sony RX100 VII||..||..||4/5||..||5/5||Jul 2019||1,199|
|Sony A6500||+ +||85/100||4.5/5||5/5||4.5/5||Oct 2016||1,399|
|Sony RX100 IV||+ +||85/100||4/5||4.5/5||4.5/5||Jun 2015||999|
|Sony RX100 II||+ +||79/100||4.5/5||5/5||4.5/5||Jun 2013||749|
|Sony A99||..||84/100||4.5/5||o||4.5/5||Sep 2012||2,799|
|Sony RX100||+ +||78/100||4/5||5/5||5/5||Jun 2012||649|
|Sony A77||91/100||81/100||..||4.5/5||5/5||Aug 2011||1,399|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
The above review scores should be interpreted with care, though. The assessments were made in relation to similar cameras of the same technological generation. 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? 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.
- Canon 2000D vs Sony RX100 III
- Canon 5D Mark IV vs Sony RX100 III
- Canon G12 vs Sony RX100 III
- Fujifilm X100T vs Pentax K-3
- Nikon D3000 vs Pentax K-3
- Nikon W150 vs Sony RX100 III
- Olympus E-510 vs Pentax K-3
- Olympus E-P2 vs Pentax K-3
- Olympus E-PL8 vs Pentax K-3
- Panasonic G1 vs Sony RX100 III
- Pentax K-3 vs Sony H300
- Sony RX100 II vs Sony RX100 III
Specifications: Pentax K-3 vs Sony RX100 III
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 Model||Pentax K-3||Sony RX100 III|
|Camera Type||Digital single lens reflex||Fixed lens compact camera|
|Camera Lens||Pentax K mount lenses||24-70mm f/1.8-2.8|
|Launch Date||October 2013||May 2014|
|Launch Price||USD 1,299||USD 799|
|Sensor Specs||Pentax K-3||Sony RX100 III|
|Sensor Format||APS-C Sensor||1" Sensor|
|Sensor Size||23.5 x 15.6 mm||13.2 x 8.8 mm|
|Sensor Area||366.6 mm2||116.16 mm2|
|Sensor Diagonal||28.2 mm||15.9 mm|
|Sensor Resolution||24.1 Megapixels||20 Megapixels|
|Image Resolution||6016 x 4000 pixels||5472 x 3648 pixels|
|Pixel Pitch||3.90 μm||2.41 μm|
|Pixel Density||6.56 MP/cm2||17.18 MP/cm2|
|Moiré control||no AA filter||Anti-Alias filter|
|Movie Capability||1080/60i Video||1080/60p Video|
|ISO Setting||100 - 51,200 ISO||100 - 12,800 ISO|
|ISO Boost||no Enhancement||80 - 25,600 ISO|
|Image Processor||PRIME III||BIONZ X|
|DXO Sensor Quality (score)||80||67|
|DXO Color Depth (bits)||23.7||22.4|
|DXO Dynamic Range (EV)||13.4||12.3|
|DXO Low Light (ISO)||1216||495|
|Screen Specs||Pentax K-3||Sony RX100 III|
|Viewfinder Type||Optical viewfinder||Electronic viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||1440k dots|
|Top-Level Screen||Control Panel||no Top Display|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.2inch||3.0inch|
|LCD Resolution||1037k dots||1229k dots|
|LCD Attachment||Fixed screen||Tilting screen|
|Shooting Specs||Pentax K-3||Sony RX100 III|
|Focus System||Phase-detect AF||Contrast-detect AF|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/8000s||1/2000s|
|Continuous Shooting||8.3 shutter flaps/s||10 shutter flaps/s|
|Time-Lapse Photography||Intervalometer built-in||no Intervalometer|
|Image Stabilization||In-body stabilization||Lens-based stabilization|
|Fill Flash||Build-in Flash||Build-in Flash|
|Storage Medium||SDXC cards||MS or SDXC cards|
|Second Storage Option||Dual card slots||Single card slot|
|UHS card support||UHS-I||UHS-I|
|Connectivity Specs||Pentax K-3||Sony RX100 III|
|External Flash||Hotshoe||no 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||no MIC socket|
|Headphone Socket||Headphone port||no Headphone port|
|Wifi Support||no Wifi||Wifi built-in|
|Near-Field Communication||no NFC||NFC built-in|
|Body Specs||Pentax K-3||Sony RX100 III|
|Environmental Sealing||Weathersealed body||not weather sealed|
|Battery Life (CIPA)||560 shots per charge||320 shots per charge|
|In-Camera Charging||no USB charging||USB charging|
131 x 100 x 77 mm
(5.2 x 3.9 x 3.0 in)
102 x 58 x 41 mm
(4.0 x 2.3 x 1.6 in)
|Camera Weight||800 g (28.2 oz)||290 g (10.2 oz)|
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