Panasonic GX8 vs Pentax K-3
The Panasonic Lumix DMC-GX8 and the Pentax K-3 are two enthusiast cameras that were announced, respectively, in July 2015 and October 2013. The GX8 is a mirrorless interchangeable lens camera, while the K-3 is a DSLR. The cameras are based on a Four Thirds (GX8) and an APS-C (K-3) sensor. The Panasonic has a resolution of 20.2 megapixels, whereas the Pentax provides 24.1 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 Panasonic Lumix DMC-GX8 and the Pentax K-3? 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 Panasonic GX8 and the Pentax K-3 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.
Both cameras are available in two different colors (black, silver).
If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax K-3 is notably larger (26 percent) than the Panasonic GX8. Moreover, the K-3 is substantially heavier (64 percent) than the GX8. 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.
The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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.
|Panasonic GX8||5.2 in||3.1 in||2.5 in||17.2 oz||330||Y||Jul 2015||1,199|
|Pentax K-3||5.2 in||3.9 in||3.0 in||28.2 oz||560||Y||Oct 2013||1,299|
|Olympus E-M1 II||5.3 in||3.6 in||2.6 in||20.2 oz||440||Y||Sep 2016||1,999|
|Olympus PEN-F||4.9 in||2.8 in||1.5 in||15.1 oz||330||n||Jan 2016||1,199|
|Olympus E-M5 II||4.9 in||3.3 in||1.8 in||16.5 oz||310||Y||Feb 2015||1,099|
|Olympus E-M1||5.1 in||3.7 in||2.5 in||17.5 oz||350||Y||Sep 2013||1,399|
|Panasonic G95||5.1 in||3.7 in||3.0 in||18.9 oz||290||Y||Apr 2019||999|
|Panasonic GX9||4.9 in||2.8 in||1.9 in||14.4 oz||260||n||Feb 2018||849|
|Panasonic G85||5.0 in||3.5 in||2.9 in||17.8 oz||330||Y||Sep 2016||899|
|Panasonic GH4||5.2 in||3.7 in||3.3 in||19.8 oz||500||Y||Feb 2014||1,499|
|Panasonic GX7||4.8 in||2.8 in||2.2 in||14.2 oz||350||n||Aug 2013||999|
|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 A6500||4.7 in||2.6 in||2.1 in||16.0 oz||350||Y||Oct 2016||1,399|
|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.|
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. The GX8 was somewhat cheaper (by 8 percent) than the K-3 at launch, but both cameras fall into the same price category. 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 size of the sensor inside a digital camera is one of the key determinants 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.
Of the two cameras under consideration, the Panasonic GX8 features a Four Thirds sensor and the Pentax K-3 an APS-C sensor. The sensor area in the K-3 is 63 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 1.5. The sensor in the GX8 has a native 4:3 aspect ratio, while the one in the K-3 offers a 3:2 aspect.
Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) sensors.
With 24.1MP, the K-3 offers a higher resolution than the GX8 (20.2MP), but the K-3 nevertheless has larger individual pixels (pixel pitch of 3.90μm versus 3.34μm for the GX8) due to its larger sensor. However, the GX8 is a somewhat more recent model (by 1 year and 9 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 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 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 Panasonic GX8 are 25.9 x 19.4 inches or 65.8 x 49.4 cm for good quality, 20.7 x 15.6 inches or 52.7 x 39.5 cm for very good quality, and 17.3 x 13 inches or 43.9 x 32.9 cm for excellent quality prints.
The Panasonic Lumix DMC-GX8 has a native sensitivity range from ISO 200 to ISO 25600, which can be extended to ISO 100-25600. The corresponding ISO settings for the Pentax K-3 are ISO 100 to ISO 51200 (no boost).
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 consideration, the K-3 has a markedly higher DXO score than the GX8 (overall score 5 points higher), which will translate into better image quality. The advantage is based on 0.2 bits higher color depth, 0.8 EV in additional dynamic range, and 0.6 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.
| DXO |
|Panasonic GX8||Four Thirds||20.2||5184||3888||4K/30p||23.5||12.6||806||75|
|Olympus E-M1 II||Four Thirds||20.2||5184||3888||4K/30p||23.7||12.8||1312||80|
|Olympus PEN-F||Four Thirds||20.2||5184||3888||1080/60p||23.1||12.4||894||74|
|Olympus E-M5 II||Four Thirds||15.9||4608||3456||1080/60p||23.0||12.5||842||73|
|Olympus E-M1||Four Thirds||15.9||4608||3456||1080/30p||23.0||12.7||757||73|
|Panasonic G95||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|Panasonic GX9||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|Panasonic G85||Four Thirds||15.8||4592||3448||4K/30p||22.8||12.5||656||71|
|Panasonic GH4||Four Thirds||15.9||4608||3456||4K/30p||23.2||12.8||791||74|
|Panasonic GX7||Four Thirds||15.8||4592||3448||1080/60p||22.6||12.2||718||70|
|Pentax K-3 II||APS-C||24.1||6016||4000||1080/60i||23.6||13.6||1106||80|
Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the GX8 provides a higher video resolution than the K-3. It can shoot video footage at 4K/30p, 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 GX8 has an electronic viewfinder (2360k 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 GX8 has a higher magnification than the one of the K-3 (0.77x vs 0.63x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The adjacent table lists some of the other core features of the Panasonic GX8 and Pentax K-3 along with similar information for a selection of comparators.
|Olympus E-M1 II||2360||n||3.0||1037||swivel||Y||1/8000s||18.0||n||Y|
|Olympus E-M5 II||2360||n||3.0||1037||swivel||Y||1/8000s||10.0||n||Y|
|Pentax K-3 II||optical||Y||3.2||1037||fixed||n||1/8000s||8.3||n||Y|
One differentiating feature between the two cameras concerns the touch sensitivity of the rear screen. The GX8 has a touchscreen, while the K-3 has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.The GX8 has an articulated LCD that can be turned to be front-facing. This characteristic will be appreciated by vloggers and photographers who are interested in snapping selfies. In contrast, the K-3 does not have a selfie-screen.
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 GX8 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 Panasonic GX8 and the Pentax K-3 both have 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.
Concerning the storage of imaging data, both the GX8 and the K-3 write their files to SDXC cards. The K-3 features dual card slots, which can be very useful in case a memory card fails. In contrast, the GX8 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 Panasonic Lumix DMC-GX8 and Pentax K-3 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|Olympus E-M1 II||Y||stereo||mono||Y||Y||micro||3.0||Y||-||-|
|Olympus E-M5 II||Y||stereo||mono||Y||-||micro||2.0||Y||-||-|
|Pentax K-3 II||Y||mono||mono||Y||Y||mini||3.0||-||-||-|
It is notable that the GX8 offers wifi support, while the K-3 does not. Wifi can be a very convenient means to transfer image data to an off-camera location.
Studio photographers will appreciate that the Pentax K-3 (unlike the GX8) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Both the GX8 and the K-3 have been discontinued, but can regularly be found used on eBay. The K-3 was replaced by the Pentax K-3 II, while the GX8 was followed by the Panasonic GX9. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official Panasonic and Pentax websites.
So what is the bottom line? Is the Panasonic GX8 better than the Pentax K-3 or vice versa? A synthesis of the relative strong points of each of the models is listed below.
Advantages of the Panasonic Lumix DMC-GX8:
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- Better video: Provides higher definition movie capture (4K/30p vs 1080/60i).
- More framing info: Has an electronic viewfinder that displays shooting data.
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.77x vs 0.63x).
- More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
- Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
- 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.
- Less disturbing: Has an electronic shutter option for completely silent shooting.
- More compact: Is smaller (133x78mm vs 131x100mm) and thus needs less room in the bag.
- Less heavy: Is lighter (by 313g or 39 percent) and hence easier to carry around.
- More legacy lens friendly: Can take a broad range of 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.
- More modern: Is somewhat more recent (announced 1 year and 9 months after the K-3).
Arguments in favor of the Pentax K-3:
- More detail: Has more megapixels (24.1 vs 20.2MP), which boosts linear resolution by 11%.
- Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
- Better image quality: Scores markedly higher (5 points) in the DXO overall evaluation.
- More dynamic range: Captures a broader range of light and dark details (0.8 EV of extra DR).
- Better low-light sensitivity: Can shoot in dim conditions (0.6 stops ISO advantage).
- Better sound control: Has a headphone port that enables audio monitoring while recording.
- Brighter framing: Features an optical viewfinder for clear, lag-free composition.
- Easier setting verification: Features a control panel on top to check shooting parameters.
- Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
- Longer lasting: Gets more shots (560 versus 330) out of a single battery charge.
- Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
- 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).
If the count of individual advantages (bullet points above) is taken as a guide, the match-up finishes in a tie (15 points each). 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. A professional wedding photographer will view the differences between cameras in a way that diverges from the perspective of a travel photog, and a person interested in cityscapes has distinct needs from a macro 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 Panasonic GX8 and the Pentax K-3 place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera and Best DSLR 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 GX8 and the K-3 in practical situations. 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 why hands-on reviews by experts are important. The adjacent summary-table relays the overall verdicts of several of the most popular 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.
|Panasonic GX8||+||82/100||4.5/5||5/5||4.5/5||Jul 2015||1,199|
|Pentax K-3||..||83/100||5/5||4.5/5||5/5||Oct 2013||1,299|
|Olympus E-M1 II||+ +||85/100||4.5/5||5/5||4.5/5||Sep 2016||1,999|
|Olympus PEN-F||..||82/100||4.5/5||4.5/5||5/5||Jan 2016||1,199|
|Olympus E-M5 II||+ +||81/100||5/5||4.5/5||5/5||Feb 2015||1,099|
|Olympus E-M1||+ +||84/100||4.5/5||4.5/5||4.5/5||Sep 2013||1,399|
|Panasonic G95||+||83/100||4.5/5||4.5/5||4.5/5||Apr 2019||999|
|Panasonic GX9||+||84/100||4.5/5||4.5/5||4.5/5||Feb 2018||849|
|Panasonic G85||+ +||84/100||5/5||4.5/5||4.5/5||Sep 2016||899|
|Panasonic GH4||+ +||85/100||5/5||5/5||5/5||Feb 2014||1,499|
|Panasonic GX7||+||79/100||5/5||4.5/5||5/5||Aug 2013||999|
|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 A6500||+ +||85/100||4.5/5||5/5||4.5/5||Oct 2016||1,399|
|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. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. 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 use the search menu below. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.
Specifications: Panasonic GX8 vs Pentax K-3
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||Panasonic GX8||Pentax K-3|
|Camera Type||Mirrorless system camera||Digital single lens reflex|
|Camera Lens||Micro Four Thirds lenses||Pentax K mount lenses|
|Launch Date||July 2015||October 2013|
|Launch Price||USD 1,199||USD 1,299|
|Sensor Specs||Panasonic GX8||Pentax K-3|
|Sensor Format||Four Thirds Sensor||APS-C Sensor|
|Sensor Size||17.3 x 13.0 mm||23.5 x 15.6 mm|
|Sensor Area||224.9 mm2||366.6 mm2|
|Sensor Diagonal||21.6 mm||28.2 mm|
|Sensor Resolution||20.2 Megapixels||24.1 Megapixels|
|Image Resolution||5184 x 3888 pixels||6016 x 4000 pixels|
|Pixel Pitch||3.34 μm||3.90 μm|
|Pixel Density||8.96 MP/cm2||6.56 MP/cm2|
|Moiré control||Anti-Alias filter||no AA filter|
|Movie Capability||4K/30p Video||1080/60i Video|
|ISO Setting||200 - 25,600 ISO||100 - 51,200 ISO|
|ISO Boost||100 - 25,600 ISO||no Enhancement|
|Image Processor||Venus||PRIME III|
|DXO Sensor Quality (score)||75||80|
|DXO Color Depth (bits)||23.5||23.7|
|DXO Dynamic Range (EV)||12.6||13.4|
|DXO Low Light (ISO)||806||1216|
|Screen Specs||Panasonic GX8||Pentax K-3|
|Viewfinder Type||Electronic viewfinder||Optical viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||2360k dots|
|Top-Level Screen||no Top Display||Control Panel|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.2inch|
|LCD Resolution||1040k dots||1037k dots|
|LCD Attachment||Swivel screen||Fixed screen|
|Touch Input||Touchscreen||no Touchscreen|
|Shooting Specs||Panasonic GX8||Pentax K-3|
|Focus System||Contrast-detect AF||Phase-detect AF|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/8000s||1/8000s|
|Continuous Shooting||10 shutter flaps/s||8.3 shutter flaps/s|
|Electronic Shutter||up to 1/16000s||no E-Shutter|
|Time-Lapse Photography||Intervalometer built-in||Intervalometer built-in|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||no On-Board Flash||Build-in Flash|
|Storage Medium||SDXC cards||SDXC cards|
|Second Storage Option||Single card slot||Dual card slots|
|UHS card support||UHS-I||UHS-I|
|Connectivity Specs||Panasonic GX8||Pentax K-3|
|Studio Flash||no PC Sync||PC Sync socket|
|USB Connector||USB 2.0||USB 3.0|
|HDMI Port||micro HDMI||mini HDMI|
|Microphone Port||External MIC port||External MIC port|
|Headphone Socket||no Headphone port||Headphone port|
|Wifi Support||Wifi built-in||no Wifi|
|Near-Field Communication||NFC built-in||no NFC|
|Body Specs||Panasonic GX8||Pentax K-3|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||330 shots per charge||560 shots per charge|
133 x 78 x 63 mm
(5.2 x 3.1 x 2.5 in)
131 x 100 x 77 mm
(5.2 x 3.9 x 3.0 in)
|Camera Weight||487 g (17.2 oz)||800 g (28.2 oz)|
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