Pentax K-3 II vs Sony RX100 III
The Pentax K-3 II and the Sony Cyber-shot DSC-RX100 III are two digital cameras that were officially introduced, respectively, in April 2015 and May 2014. The K-3 II is a DSLR, while the RX100 III is a fixed lens compact. The cameras are based on an APS-C (K-3 II) 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 II 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.
The physical size and weight of the Pentax K-3 II and the Sony RX100 III are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive views from the front, the top, and the rear side are shown. All size dimensions are rounded to the nearest millimeter.
The K-3 II 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 II. It is worth mentioning in this context that the K-3 II 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 II 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 II gets 720 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 table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. If you would like to visualize and compare a different camera combination, you can navigate to the CAM-parator app and make your selection from a broad list of cameras there.
|1.||Pentax K-3 II||131 mm||100 mm||77 mm||800 g||720||Y||Apr 2015||1,099|
|2.||Sony RX100 III||102 mm||58 mm||41 mm||290 g||320||n||May 2014||799|
|3.||Canon 80D||139 mm||105 mm||79 mm||730 g||960||Y||Feb 2016||1,199|
|4.||Canon G7 X||103 mm||60 mm||40 mm||304 g||210||n||Sep 2014||699|
|5.||Nikon D7200||136 mm||107 mm||76 mm||765 g||1110||Y||Mar 2015||1,199|
|6.||Pentax K-3 III||135 mm||104 mm||74 mm||820 g||800||Y||Mar 2021||1,999|
|7.||Pentax KP||132 mm||101 mm||76 mm||703 g||390||Y||Jan 2017||1,099|
|8.||Pentax K-70||126 mm||93 mm||74 mm||688 g||410||Y||Jun 2016||649|
|9.||Pentax K-S2||123 mm||91 mm||73 mm||678 g||410||Y||Feb 2015||749|
|10.||Pentax K-S1||121 mm||93 mm||70 mm||558 g||410||n||Aug 2014||749|
|11.||Pentax K-3||131 mm||100 mm||77 mm||800 g||560||Y||Oct 2013||1,299|
|12.||Pentax K-5 II||131 mm||97 mm||73 mm||760 g||740||Y||Sep 2012||1,099|
|13.||Pentax K-5||131 mm||97 mm||73 mm||760 g||740||Y||Sep 2010||1,099|
|14.||Sony RX100 VII||102 mm||58 mm||43 mm||302 g||260||n||Jul 2019||1,199|
|15.||Sony RX100 IV||102 mm||58 mm||41 mm||298 g||280||n||Jun 2015||999|
|16.||Sony RX100 II||102 mm||58 mm||38 mm||281 g||350||n||Jun 2013||749|
|17.||Sony RX100||102 mm||58 mm||36 mm||240 g||330||n||Jun 2012||649|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
Any camera decision will obviously take relative prices into account. 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 II, 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.
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. Moreover, a large sensor camera will give the photographer more control over depth-of-field in the image and, thus, the ability to better 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 II 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 II offers a higher resolution than the RX100 III (20MP), but the K-3 II nevertheless has larger individual pixels (pixel pitch of 3.90μm versus 2.41μm for the RX100 III) due to its larger sensor. Moreover, the K-3 II is a somewhat more recent model (by 11 months) than the RX100 III, and its sensor might have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixels. Coming back to sensor resolution, it should be mentioned that the K-3 II 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 II implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the K-3 II 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.
Unlike the RX100 III, the K-3 II has the capacity to capture high quality composite images by combining multiple shots after shifting its sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).
The Pentax K-3 II 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 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 II provides substantially higher image quality than the RX100 III, with an overall score that is 13 points higher. This advantage is based on 1.2 bits higher color depth, 1.3 EV in additional dynamic range, and 1.2 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.
| DXO |
|1.||Pentax K-3 II||APS-C||24.1||6016||4000||1080/60i||23.6||13.6||1106||80|
|2.||Sony RX100 III||1-inch||20.0||5472||3648||1080/60p||22.4||12.3||495||67|
|4.||Canon G7 X||1-inch||20.0||5472||3648||1080/60p||23.0||12.7||556||71|
|6.||Pentax K-3 III||APS-C||25.6||6192||4128||4K/30p||..||..||..||..|
|12.||Pentax K-5 II||APS-C||16.1||4928||3264||1080/25p||23.8||14.1||1235||82|
|14.||Sony RX100 VII||1-inch||20.0||5472||3648||4K/30p||21.8||12.4||418||63|
|15.||Sony RX100 IV||1-inch||20.0||5472||3648||4K/30p||22.8||12.6||591||70|
|16.||Sony RX100 II||1-inch||20.0||5472||3648||1080/60p||22.5||12.4||483||67|
Many modern cameras cannot only take still pictures, but also record videos. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the RX100 III provides a faster frame rate than the K-3 II. It can shoot movie footage at 1080/60p, while the Pentax is limited to 1080/60i.
Apart from body and sensor, cameras can and do differ across a variety of features. For example, the RX100 III has an electronic viewfinder (1440k dots), while the K-3 II 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 II has a higher magnification than the one of the RX100 III (0.63x vs 0.59x), 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 II and Sony RX100 III in connection with corresponding information for a sample of similar cameras.
|1.||Pentax K-3 II||optical||Y||3.2||1037||fixed||n||1/8000s||8.3||n||Y|
|2.||Sony RX100 III||1440||n||3.0||1229||tilting||n||1/2000s||10.0||Y||Y|
|4.||Canon G7 X||none||n||3.0||1040||tilting||Y||1/2000s||6.5||Y||Y|
|6.||Pentax K-3 III||optical||Y||3.2||1620||fixed||Y||1/8000s||12.0||n||Y|
|12.||Pentax K-5 II||optical||Y||3.0||921||fixed||n||1/8000s||7.0||Y||Y|
|14.||Sony RX100 VII||2359||n||3.0||921||tilting||Y||1/2000s||90.0||Y||Y|
|15.||Sony RX100 IV||2359||n||3.0||1228||tilting||n||1/2000s||16.0||Y||Y|
|16.||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 II, 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 II does not have a selfie-screen.
The Pentax K-3 II 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 II writes its imaging data to SDXC cards, while the RX100 III uses SDXC or Memory Stick PRO Duo cards. The K-3 II 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 II 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 |
| NFC |
|1.||Pentax K-3 II||Y||mono||mono||Y||Y||mini||3.0||-||-||-|
|2.||Sony RX100 III||-||stereo||mono||-||-||micro||2.0||Y||Y||-|
|4.||Canon G7 X||-||stereo||mono||-||-||micro||2.0||Y||Y||-|
|6.||Pentax K-3 III||Y||stereo||mono||Y||Y||micro||3.2||Y||-||Y|
|12.||Pentax K-5 II||Y||stereo||mono||Y||-||mini||2.0||-||-||-|
|14.||Sony RX100 VII||-||stereo||mono||Y||-||micro||2.0||Y||Y||Y|
|15.||Sony RX100 IV||-||stereo||mono||-||-||micro||2.0||Y||Y||-|
|16.||Sony RX100 II||Y||stereo||mono||-||-||micro||2.0||Y||Y||-|
It is notable that the K-3 II 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 II (unlike the RX100 III) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Travel and landscape photographers will find it useful that the K-3 II has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.
Both the K-3 II and the RX100 III have been discontinued, but can regularly be found used on eBay. The RX100 III was replaced by the Sony RX100 IV, while the K-3 II was followed by the Pentax K-3 III. 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 what is the bottom line? Is there a clear favorite between the Pentax K-3 II and the Sony RX100 III? Which camera is better? The listing below highlights the relative strengths of the two models.
Advantages of the Pentax K-3 II:
- 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.
- High quality composites: Can combine several shots after pixel-shifting its sensor.
- Better image quality: Scores substantially higher (13 points) in the DXO overall assessment.
- Richer colors: Generates images with noticeably better colors (1.2 bits more color depth).
- More dynamic range: Captures a larger spectrum of light and dark details (1.3 EV of extra DR).
- Better low-light sensitivity: Requires less light for good images (1.2 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 0.59x).
- 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 (720 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.
- Easier geotagging: Features an internal GPS sensor to log localization data.
- 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 modern: Is somewhat more recent (announced 11 months after the RX100 III).
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 II 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 II).
- Easier travel charging: Can be conveniently charged via its USB port.
- Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
- 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 heavily discounted: Has been on the market for longer (launched in May 2014).
If the count of individual advantages (bullet points above) is taken as a guide, the K-3 II is the clear winner of the match-up (24 : 16 points). However, the pertinence of the various camera strengths will differ across photographers, so that you might want to weigh individual camera traits according to their importance for your own imaging needs before making a camera decision. 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 II 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 the spec-sheets of cameras can offer a general idea of their imaging potential, it remains incomplete and does no justice, for example, to the way the K-3 II or the RX100 III perform in practice. User reviews that are available, for instance, at amazon can sometimes shed light on these issues, but such feedback is all too often partial, inconsistent, and inaccurate.
This is where reviews by experts come in. The adjacent summary-table relays the overall verdicts of several of the most popular camera review sites (amateurphotographer [AP], cameralabs [CL], dpreview [DPR], ephotozine [EPZ], photographyblog [PB]). 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.
|1.||Pentax K-3 II||4.5/5||..||..||5/5||5/5||Apr 2015||1,099|
|2.||Sony RX100 III||5/5||+ +||82/100||4.5/5||5/5||May 2014||799|
|3.||Canon 80D||4/5||+ +||84/100||4.5/5||4.5/5||Feb 2016||1,199|
|4.||Canon G7 X||4/5||+ +||77/100||4.5/5||4.5/5||Sep 2014||699|
|5.||Nikon D7200||4/5||+ +||84/100||4.5/5||4.5/5||Mar 2015||1,199|
|6.||Pentax K-3 III||..||..||..||..||..||Mar 2021||1,999|
|7.||Pentax KP||4/5||..||82/100||5/5||4.5/5||Jan 2017||1,099|
|8.||Pentax K-70||4.5/5||..||79/100||4.5/5||4.5/5||Jun 2016||649|
|9.||Pentax K-S2||4.5/5||..||..||5/5||4.5/5||Feb 2015||749|
|10.||Pentax K-S1||4/5||..||..||4.5/5||4/5||Aug 2014||749|
|11.||Pentax K-3||4/5||..||83/100||5/5||5/5||Oct 2013||1,299|
|12.||Pentax K-5 II||5/5||..||80/100||5/5||4.5/5||Sep 2012||1,099|
|13.||Pentax K-5||4/5||..||83/100||5/5||4.5/5||Sep 2010||1,099|
|14.||Sony RX100 VII||4.5/5||..||..||4/5||5/5||Jul 2019||1,199|
|15.||Sony RX100 IV||4.5/5||+ +||85/100||4/5||4.5/5||Jun 2015||999|
|16.||Sony RX100 II||5/5||+ +||79/100||4.5/5||4.5/5||Jun 2013||749|
|17.||Sony RX100||5/5||+ +||78/100||4/5||5/5||Jun 2012||649|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
Care should be taken when interpreting the review scores above, 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 comparisons of ratings among very different cameras or across long time periods have little meaning. 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? In case you are interested in seeing how other cameras pair up, just make a corresponding selection in the search boxes below. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.
Specifications: Pentax K-3 II 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 II||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||April 2015||May 2014|
|Launch Price||USD 1,099||USD 799|
|Sensor Specs||Pentax K-3 II||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)||23.6||22.4|
|DXO Dynamic Range (EV)||13.6||12.3|
|DXO Low Light (ISO)||1106||495|
|Screen Specs||Pentax K-3 II||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 II||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||no On-Board 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 II||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|
|Geotagging||GPS built-in||no internal GPS|
|Body Specs||Pentax K-3 II||Sony RX100 III|
|Environmental Sealing||Weathersealed body||not weather sealed|
|Battery Life (CIPA)||720 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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