Panasonic GX9 vs Sony A7S III
The Panasonic Lumix DC-GX9 and the Sony Alpha 7S III are two digital cameras that were revealed to the public, respectively, in February 2018 and July 2020. Both the GX9 and the A7S III are mirrorless interchangeable lens cameras that are based on a Four Thirds (GX9) and a full frame (A7S III) sensor. The Panasonic has a resolution of 20.2 megapixels, whereas the Sony provides 12 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 DC-GX9 and the Sony Alpha 7S 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 Panasonic GX9 and the Sony A7S III are illustrated 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 width, height and depth dimensions are rounded to the nearest millimeter.
The GX9 can be obtained in two different colors (black, silver), while the A7S 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 A7S III is notably larger (38 percent) than the Panasonic GX9. Moreover, the A7S III is substantially heavier (72 percent) than the GX9. It is noteworthy in this context that the A7S III is splash and dust-proof, while the GX9 does not feature any corresponding weather-sealing.
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. A larger imaging sensor will tend to go along with bigger and heavier lenses, although exceptions exist. You can compare the optics available for the two cameras in the Micro Four Thirds Lens Catalog (GX9) and the Sony FE Lens Catalog (A7S III). Mirrorless cameras, such as the two under consideration, have the additional advantage of having a short flange to focal plane distance, which makes it possible to mount many lenses from other systems onto the camera via adapters.
Concerning battery life, the GX9 gets 260 shots out of its DMW-BLG10 battery, while the A7S III can take 600 images on a single charge of its NP-FZ100 power pack. The battery packs of both cameras can be charged via USB, which can be very convenient when travelling.
The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. If you want to switch the focus of the display and review another camera pair, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.
|1.||Panasonic GX9||124 mm||72 mm||47 mm||407 g||260||n||Feb 2018||849|
|2.||Sony A7S III||127 mm||97 mm||81 mm||699 g||600||Y||Jul 2020||3,499|
|3.||Olympus E-M10 IV||122 mm||84 mm||49 mm||383 g||360||n||Aug 2020||699|
|4.||Olympus E-M10 III||122 mm||84 mm||50 mm||410 g||330||n||Aug 2017||649|
|5.||Olympus PEN-F||125 mm||72 mm||37 mm||427 g||330||n||Jan 2016||1,199|
|6.||Olympus E-M10 II||120 mm||83 mm||47 mm||390 g||320||n||Aug 2015||649|
|7.||Panasonic G95||130 mm||94 mm||77 mm||536 g||290||Y||Apr 2019||999|
|8.||Panasonic LX100 II||115 mm||66 mm||65 mm||392 g||300||n||Aug 2018||999|
|9.||Panasonic ZS200||111 mm||65 mm||45 mm||340 g||370||n||Feb 2018||799|
|10.||Panasonic GX85||122 mm||71 mm||44 mm||426 g||290||n||Apr 2016||799|
|11.||Panasonic GX8||133 mm||78 mm||63 mm||487 g||330||Y||Jul 2015||1,199|
|12.||Panasonic GX7||123 mm||71 mm||55 mm||402 g||350||n||Aug 2013||999|
|13.||Sony A7R IV||129 mm||96 mm||78 mm||665 g||670||Y||Jul 2019||3,499|
|14.||Sony A7R III||127 mm||96 mm||74 mm||650 g||650||Y||Oct 2017||3,199|
|15.||Sony A9||127 mm||96 mm||63 mm||673 g||650||Y||Apr 2017||4,499|
|16.||Sony A7R II||127 mm||96 mm||60 mm||625 g||290||Y||Jun 2015||3,199|
|17.||Sony A7S II||127 mm||96 mm||60 mm||627 g||370||Y||Sep 2015||2,999|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
Any camera decision will naturally be influenced heavily by the price. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The GX9 was launched at a markedly lower price (by 76 percent) than the A7S III, which puts it into a different market segment. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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. 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. 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 associated with larger, more expensive camera bodies and lenses.
Of the two cameras under consideration, the Panasonic GX9 features a Four Thirds sensor and the Sony A7S III a full frame sensor. The sensor area in the A7S III is 276 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 1.0. The sensor in the GX9 has a native 4:3 aspect ratio, while the one in the A7S III offers a 3:2 aspect.
Despite having a smaller sensor, the Panasonic GX9 offers a higher resolution of 20.2 megapixels, compared with 12 MP of the Sony A7S III. This megapixels advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.34μm versus 8.40μm for the A7S III). Moreover, it should be noted that the A7S III is much more recent (by 2 years and 5 months) than the GX9, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixel-units. Coming back to sensor resolution, it should be mentioned that the GX9 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.
The resolution advantage of the Panasonic GX9 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the GX9 for good quality output (200 dots per inch) amounts to 25.9 x 19.4 inches or 65.8 x 49.4 cm, for very good quality (250 dpi) 20.7 x 15.6 inches or 52.7 x 39.5 cm, and for excellent quality (300 dpi) 17.3 x 13 inches or 43.9 x 32.9 cm. The corresponding values for the Sony A7S III are 21.2 x 14.2 inches or 53.8 x 36 cm for good quality, 17 x 11.3 inches or 43.1 x 28.8 cm for very good quality, and 14.1 x 9.4 inches or 35.9 x 24 cm for excellent quality prints.
The Panasonic Lumix DC-GX9 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 Sony Alpha 7S III are ISO 80 to ISO 102400, with the possibility to increase the ISO range to 40-409600.
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"). The table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar cameras.
| DXO |
|1.||Panasonic GX9||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|2.||Sony A7S III||Full Frame||12.0||4240||2832||4K/120p||23.7||13.9||2520||86|
|3.||Olympus E-M10 IV||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|4.||Olympus E-M10 III||Four Thirds||15.9||4608||3456||4K/30p||..||..||..||..|
|5.||Olympus PEN-F||Four Thirds||20.2||5184||3888||1080/60p||23.1||12.4||894||74|
|6.||Olympus E-M10 II||Four Thirds||15.9||4608||3456||1080/60p||23.1||12.5||842||73|
|7.||Panasonic G95||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|8.||Panasonic LX100 II||Four Thirds||16.8||4736||3552||4K/30p||..||..||..||..|
|10.||Panasonic GX85||Four Thirds||15.8||4592||3448||4K/30p||22.9||12.6||662||71|
|11.||Panasonic GX8||Four Thirds||20.2||5184||3888||4K/30p||23.5||12.6||806||75|
|12.||Panasonic GX7||Four Thirds||15.8||4592||3448||1080/60p||22.6||12.2||718||70|
|13.||Sony A7R IV||Full Frame||60.2||9504||6336||4K/30p||26.0||14.8||3344||99|
|14.||Sony A7R III||Full Frame||42.2||7952||5304||4K/30p||26.0||14.7||3523||100|
|15.||Sony A9||Full Frame||24.0||6000||4000||4K/30p||24.9||13.3||3517||92|
|16.||Sony A7R II||Full Frame||42.2||7952||5304||4K/30p||26.0||13.9||3434||98|
|17.||Sony A7S II||Full Frame||12.0||4240||2832||4K/30p||23.6||13.3||2993||85|
Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the A7S III provides a faster frame rate than the GX9. It can shoot movie footage at 4K/120p, while the Panasonic is limited to 4K/30p.
Apart from body and sensor, cameras can and do differ across a variety of features. The two cameras under review are similar with respect to both having an electronic viewfinder. However, the one in the A7S III offers a substantially higher resolution than the one in the GX9 (9440k vs 2760k dots). The adjacent table lists some of the other core features of the Panasonic GX9 and Sony A7S III along with similar information for a selection of comparators.
|2.||Sony A7S III||9440||n||3.0||1440||swivel||Y||1/8000s||10.0||n||Y|
|3.||Olympus E-M10 IV||2360||n||3.0||1040||tilting||Y||1/4000s||15.0||Y||Y|
|4.||Olympus E-M10 III||2360||n||3.0||1040||tilting||Y||1/4000s||8.6||Y||Y|
|6.||Olympus E-M10 II||2360||n||3.0||1040||tilting||Y||1/4000s||8.0||Y||Y|
|8.||Panasonic LX100 II||2764||n||3.0||1240||fixed||Y||1/4000s||11.0||n||Y|
|13.||Sony A7R IV||5760||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|14.||Sony A7R III||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|16.||Sony A7R II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
|17.||Sony A7S II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
One difference between the cameras concerns the presence of an on-board flash. The GX9 has one, while the A7S III does not. While the built-in flash of the GX9 is not very powerful, it can at times be useful as a fill-in light.The A7S 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 GX9 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, both cameras under consideration feature an 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 GX9 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 GX9 writes its imaging data to SDXC cards, while the A7S III uses CFexpress or SDXC cards. The A7S III features dual card slots, which can be very useful in case a memory card fails. In contrast, the GX9 only has one slot. The A7S III supports UHS-II cards (on both slots), while the GX9 can use UHS-I cards.
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 DC-GX9 and Sony Alpha 7S III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|2.||Sony A7S III||Y||stereo||mono||Y||Y||full||3.2||Y||-||Y|
|3.||Olympus E-M10 IV||Y||stereo||mono||-||-||micro||2.0||Y||-||Y|
|4.||Olympus E-M10 III||Y||stereo||mono||-||-||micro||2.0||Y||-||-|
|6.||Olympus E-M10 II||Y||stereo||mono||-||-||micro||2.0||Y||-||-|
|8.||Panasonic LX100 II||Y||stereo||mono||-||-||micro||2.0||Y||-||Y|
|13.||Sony A7R IV||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|14.||Sony A7R III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|16.||Sony A7R II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|17.||Sony A7S II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
It is notable that the A7S III has a headphone jack, which makes it possible to attach external headphones and monitor the quality of sound during the recording process. The GX9 lacks such a headphone port.
Both the GX9 and the A7S III are recent models that are part of the current product line-up. The GX9 replaced the earlier Panasonic GX8, while the A7S III followed on from the Sony A7S II. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official Panasonic and Sony websites.
So how do things add up? Is there a clear favorite between the Panasonic GX9 and the Sony A7S III? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.
Arguments in favor of the Panasonic Lumix DC-GX9:
- More detail: Offers more megapixels (20.2 vs 12MP) with a 27% higher linear resolution.
- Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- More compact: Is smaller (124x72mm vs 127x97mm) and thus needs less room in the bag.
- Less heavy: Is lighter (by 292g or 42 percent) and hence easier to carry around.
- Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
- More affordable: Was introduced into a lower priced category (76 percent cheaper at launch).
- More heavily discounted: Has been available for much longer (launched in February 2018).
Advantages of the Sony Alpha 7S III:
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- Better image quality: Is equipped with a larger and more technologically advanced sensor.
- Richer colors: The sensor size advantage translates into images with better, more accurate colors.
- More dynamic range: Larger sensor captures a wider spectrum of light and dark details.
- Better low-light sensitivity: Larger sensor produces good images even in poorly lit environments.
- Better video: Provides higher movie framerates (4K/120p versus 4K/30p).
- 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.
- More detailed viewfinder: Has higher resolution electronic viewfinder (9440k vs 2760k dots).
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.91x vs 0.70x).
- More detailed LCD: Has a higher resolution rear screen (1440k vs 1240k dots).
- More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Longer lasting: Gets more shots (600 versus 260) out of a single battery charge.
- Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
- Faster data transfer: Supports a more advanced USB protocol (3.2 vs 2.0).
- More solid recording: Has a full-sized HDMI port for a sturdy connection to an external recorder.
- Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
- Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
- More modern: Reflects 2 years and 5 months of technical progress since the GX9 launch.
If the count of individual advantages (bullet points above) is taken as a guide, the A7S III is the clear winner of the contest (21 : 8 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 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 GX9 and the Sony A7S III place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera listing whether the two cameras rank among the cream of the crop.
In any case, while the specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it remains incomplete and does no justice, for example, to the way the GX9 or the A7S 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 why hands-on reviews by experts are important. The following table reports the overall ratings of the cameras as published by some of the major 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.||Panasonic GX9||4/5||+||84/100||4.5/5||4.5/5||Feb 2018||849|
|2.||Sony A7S III||..||+ +||91/100||4.5/5||5/5||Jul 2020||3,499|
|3.||Olympus E-M10 IV||4.5/5||..||..||4.5/5||4.5/5||Aug 2020||699|
|4.||Olympus E-M10 III||..||+||80/100||4.5/5||4.5/5||Aug 2017||649|
|5.||Olympus PEN-F||..||..||82/100||4.5/5||5/5||Jan 2016||1,199|
|6.||Olympus E-M10 II||4.5/5||+ +||80/100||5/5||5/5||Aug 2015||649|
|7.||Panasonic G95||4.5/5||+||83/100||4.5/5||4.5/5||Apr 2019||999|
|8.||Panasonic LX100 II||4.5/5||+||82/100||4.5/5||4.5/5||Aug 2018||999|
|9.||Panasonic ZS200||..||+ +||81/100||4.5/5||4.5/5||Feb 2018||799|
|10.||Panasonic GX85||4.5/5||+ +||82/100||5/5||5/5||Apr 2016||799|
|11.||Panasonic GX8||5/5||+||82/100||4.5/5||4.5/5||Jul 2015||1,199|
|12.||Panasonic GX7||4/5||+||79/100||5/5||5/5||Aug 2013||999|
|13.||Sony A7R IV||5/5||+||91/100||4.5/5||5/5||Jul 2019||3,499|
|14.||Sony A7R III||..||+ +||90/100||4.5/5||5/5||Oct 2017||3,199|
|15.||Sony A9||5/5||+ +||89/100||5/5||5/5||Apr 2017||4,499|
|16.||Sony A7R II||5/5||+ +||90/100||5/5||5/5||Jun 2015||3,199|
|17.||Sony A7S II||5/5||+||..||4.5/5||5/5||Sep 2015||2,999|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
Care should be taken when interpreting the review scores above, though. The ratings are only valid when referring to cameras in the same category and of the same age. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, and comparisons of ratings among very different cameras or across long time periods have little meaning. 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? If you would like to see a different side-by-side camera review, just use the search menu below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.
Specifications: Panasonic GX9 vs Sony A7S 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||Panasonic GX9||Sony A7S III|
|Camera Type||Mirrorless system camera||Mirrorless system camera|
|Camera Lens||Micro Four Thirds lenses||Sony E mount lenses|
|Launch Date||February 2018||July 2020|
|Launch Price||USD 849||USD 3,499|
|Sensor Specs||Panasonic GX9||Sony A7S III|
|Sensor Format||Four Thirds Sensor||Full Frame Sensor|
|Sensor Size||17.3 x 13.0 mm||35.6 x 23.8 mm|
|Sensor Area||224.9 mm2||847.28 mm2|
|Sensor Diagonal||21.6 mm||42.8 mm|
|Sensor Resolution||20.2 Megapixels||12 Megapixels|
|Image Resolution||5184 x 3888 pixels||4240 x 2832 pixels|
|Pixel Pitch||3.34 μm||8.40 μm|
|Pixel Density||8.96 MP/cm2||1.42 MP/cm2|
|Moiré control||no AA filter||Anti-Alias filter|
|Movie Capability||4K/30p Video||4K/120p Video|
|ISO Setting||200 - 25,600 ISO||80 - 102,400 ISO|
|ISO Boost||100 - 25,600 ISO||40 - 409,600 ISO|
|Image Processor||Venus||BIONZ XR|
|DXO Sensor Quality (score)||..||86|
|DXO Color Depth (bits)||..||23.7|
|DXO Dynamic Range (EV)||..||13.9|
|DXO Low Light (ISO)||..||2520|
|Screen Specs||Panasonic GX9||Sony A7S III|
|Viewfinder Type||Electronic viewfinder||Electronic viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||2760k dots||9440k dots|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||1240k dots||1440k dots|
|LCD Attachment||Tilting screen||Swivel screen|
|Shooting Specs||Panasonic GX9||Sony A7S III|
|Focus System||Contrast-detect AF||Contrast-detect AF|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/4000s||1/8000s|
|Continuous Shooting||9 shutter flaps/s||10 shutter flaps/s|
|Electronic Shutter||up to 1/16000s||YES|
|Time-Lapse Photography||Intervalometer built-in||no Intervalometer|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||Build-in Flash||no On-Board Flash|
|Storage Medium||SDXC cards||CFexpress or SDXC cards|
|Second Storage Option||Single card slot||Dual card slots|
|UHS card support||UHS-I||Dual UHS-II|
|Connectivity Specs||Panasonic GX9||Sony A7S III|
|USB Connector||USB 2.0||USB 3.2|
|HDMI Port||micro HDMI||full HDMI|
|Microphone Port||no MIC socket||External MIC port|
|Headphone Socket||no Headphone port||Headphone port|
|Wifi Support||Wifi built-in||Wifi built-in|
|Bluetooth Support||Bluetooth built-in||Bluetooth built-in|
|Body Specs||Panasonic GX9||Sony A7S III|
|Environmental Sealing||not weather sealed||Weathersealed body|
|Battery Life (CIPA)||260 shots per charge||600 shots per charge|
|In-Camera Charging||USB charging||USB charging|
124 x 72 x 47 mm
(4.9 x 2.8 x 1.9 in)
127 x 97 x 81 mm
(5.0 x 3.8 x 3.2 in)
|Camera Weight||407 g (14.4 oz)||699 g (24.7 oz)|
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