Panasonic GX9 vs Sony A7 III
The Panasonic Lumix DC-GX9 and the Sony Alpha A7 III are two enthusiast cameras that were revealed to the public in February 2018. Both the GX9 and the A7 III are mirrorless interchangeable lens cameras that are based on a Four Thirds (GX9) and a full frame (A7 III) sensor. The Panasonic has a resolution of 20.2 megapixels, whereas the Sony provides 24 MP.
Below is an overview of the main specs of the two cameras as a starting point for the comparison.
|Panasonic GX9||Sony A7 III|
|Mirrorless system camera||Mirrorless system camera|
|Micro Four Thirds lenses||Sony E mount lenses|
|20.2 MP, Four Thirds Sensor||24 MP, Full Frame Sensor|
|4K/30p Video||4K/30p Video|
|ISO 200-25,600||ISO 100-51,200 (50 - 204,800)|
|Electronic viewfinder (2760k dots)||Electronic viewfinder (2359k dots)|
|3.0 LCD, 1240k dots||3.0 LCD, 922k dots|
|Tilting touchscreen||Tilting touchscreen|
|9 shutter flaps per second||10 shutter flaps per second|
|In-body stabilization||In-body stabilization|
|not weather sealed||Weathersealed body|
|260 shots per battery charge||610 shots per battery charge|
|124 x 72 x 47 mm, 407 g||127 x 96 x 74 mm, 650 g|
Going beyond this snapshot of core features and characteristics, what are the differences between the Panasonic Lumix DC-GX9 and the Sony Alpha A7 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 side-by-side display below illustrates the physical size and weight of the Panasonic GX9 and the Sony A7 III. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear are shown. All width, height and depth measures are rounded to the nearest millimeter.
The GX9 can be obtained in two different colors (black, silver), while the A7 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 A7 III is notably larger (37 percent) than the Panasonic GX9. Moreover, the A7 III is substantially heavier (60 percent) than the GX9. It is noteworthy in this context that the A7 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 (A7 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 A7 III can take 610 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 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.
|Panasonic GX9||124 mm||72 mm||47 mm||407 g||260||n||Feb 2018||849|
|Sony A7 III||127 mm||96 mm||74 mm||650 g||610||Y||Feb 2018||1,999|
|Canon M6||112 mm||68 mm||45 mm||390 g||295||n||Feb 2017||779|
|Fujifilm X-E3||121 mm||74 mm||43 mm||337 g||350||n||Sep 2017||899|
|Nikon Z6||134 mm||101 mm||67 mm||675 g||310||Y||Aug 2018||1,999|
|Olympus E-M10 IV||122 mm||84 mm||49 mm||383 g||360||n||Aug 2020||699|
|Panasonic G90||130 mm||94 mm||77 mm||536 g||290||Y||Apr 2019||999|
|Panasonic LX100 II||115 mm||66 mm||65 mm||392 g||300||n||Aug 2018||999|
|Panasonic TZ200||111 mm||65 mm||45 mm||340 g||370||n||Feb 2018||799|
|Panasonic GH5||139 mm||98 mm||87 mm||725 g||410||Y||Jan 2017||1,999|
|Panasonic GX80||122 mm||71 mm||44 mm||426 g||290||n||Apr 2016||799|
|Panasonic GX8||133 mm||78 mm||63 mm||487 g||330||Y||Jul 2015||1,199|
|Panasonic GX7||123 mm||71 mm||55 mm||402 g||350||n||Aug 2013||999|
|Sony A9 II||129 mm||96 mm||76 mm||678 g||690||Y||Oct 2019||4,499|
|Sony A7R III||127 mm||96 mm||74 mm||650 g||650||Y||Oct 2017||3,199|
|Sony A9||127 mm||96 mm||63 mm||673 g||650||Y||Apr 2017||4,499|
|Sony A7 II||127 mm||96 mm||60 mm||599 g||350||Y||Nov 2014||1,999|
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 obviously take relative prices into account. 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 58 percent) than the A7 III, which puts it into a different market segment. 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. Further, a large sensor camera will give the photographer additional creative options when using shallow depth-of-field to isolate a subject from its background. On the downside, larger sensors are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.
Of the two cameras under consideration, the Panasonic GX9 features a Four Thirds sensor and the Sony A7 III a full frame sensor. The sensor area in the A7 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 A7 III offers a 3:2 aspect.
With 24MP, the A7 III offers a higher resolution than the GX9 (20.2MP), but the A7 III nevertheless has larger individual pixels (pixel pitch of 5.94μm versus 3.34μm for the GX9) due to its larger sensor. It is noteworthy in this context that the two cameras were released in close succession, so that their sensors are from the same technological generation. Coming back to sensor resolution, it should be mentioned that the GX9 has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.
The resolution advantage of the Sony A7 III implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A7 III for good quality output (200 dots per inch) amounts to 30 x 20 inches or 76.2 x 50.8 cm, for very good quality (250 dpi) 24 x 16 inches or 61 x 40.6 cm, and for excellent quality (300 dpi) 20 x 13.3 inches or 50.8 x 33.9 cm. The corresponding values for the Panasonic GX9 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 A7 III has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.
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 A7 III are ISO 100 to ISO 51200, with the possibility to increase the ISO range to 50-204800.
For many cameras, data on sensor performance has been reported by DXO Mark. 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"). The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.
|Panasonic GX9||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|Sony A7 III||Full Frame||24.0||6000||4000||4K/30p||25.0||14.7||3730||96|
|Nikon Z6||Full Frame||24.3||6048||4024||4K/30p||25.3||14.3||3299||95|
|Olympus E-M10 IV||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|Panasonic G90||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|Panasonic LX100 II||Four Thirds||16.8||4736||3552||4K/30p||..||..||..||..|
|Panasonic GH5||Four Thirds||20.2||5184||3888||4K/60p||23.9||13.0||807||77|
|Panasonic GX80||Four Thirds||15.8||4592||3448||4K/30p||22.9||12.6||662||71|
|Panasonic GX8||Four Thirds||20.2||5184||3888||4K/30p||23.5||12.6||806||75|
|Panasonic GX7||Four Thirds||15.8||4592||3448||1080/60p||22.6||12.2||718||70|
|Sony A9 II||Full Frame||24.0||6000||4000||4K/30p||25.0||14.0||3434||93|
|Sony A7R III||Full Frame||42.2||7952||5304||4K/30p||26.0||14.7||3523||100|
|Sony A9||Full Frame||24.0||6000||4000||4K/30p||24.9||13.3||3517||92|
|Sony A7 II||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
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, and both provide the same movie specifications (4K/30p).
Apart from body and sensor, cameras can and do differ across a variety of features. The two cameras under consideration are similar with respect to both having an electronic viewfinder. However, the one in the GX9 offers a higher resolution than the one in the A7 III (2760k vs 2359k dots). The following table reports on some other key feature differences and similarities of the Panasonic GX9, the Sony A7 III, and comparable cameras.
|Sony A7 III||2359||n||3.0||922||tilting||Y||1/8000s||10.0||n||Y|
|Olympus E-M10 IV||2360||n||3.0||1040||tilting||Y||1/4000s||15.0||Y||Y|
|Panasonic LX100 II||2764||n||3.0||1240||fixed||Y||1/4000s||11.0||n||Y|
|Sony A9 II||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|Sony A7R III||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|Sony A7 II||2400||n||3.0||1230||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 A7 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 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 and the Sony A7 III 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.
The GX9 writes its imaging data to SDXC cards, while the A7 III uses SDXC or Memory Stick PRO Duo cards. The A7 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 A7 III supports UHS-II cards (on its first slot), 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 A7 III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
|Sony A7 III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|Olympus E-M10 IV||Y||stereo||mono||-||-||micro||2.0||Y||-||Y|
|Panasonic LX100 II||Y||stereo||mono||-||-||micro||2.0||Y||-||Y|
|Sony A9 II||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|Sony A7R III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|Sony A7 II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
It is notable that the A7 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 A7 III are recent models that are part of the current product line-up. The GX9 replaced the earlier Panasonic GX8, while the A7 III followed on from the Sony A7 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 what conclusions can be drawn? Is there a clear favorite between the Panasonic GX9 and the Sony A7 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:
- Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
- More detailed viewfinder: Has higher resolution electronic viewfinder (2760k vs 2359k dots).
- More detailed LCD: Has a higher resolution rear screen (1240k vs 922k dots).
- More compact: Is smaller (124x72mm vs 127x96mm) and thus needs less room in the bag.
- Less heavy: Is lighter (by 243g or 37 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 (58 percent cheaper at launch).
Reasons to prefer the Sony Alpha A7 III:
- More detail: Has more megapixels (24 vs 20.2MP), which boosts linear resolution by 11%.
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- Better image quality: Features bigger pixels on a larger sensor for higher quality imaging.
- Richer colors: The pixel size advantage translates into images with better, more accurate colors.
- More dynamic range: Larger pixels capture a wider spectrum of light and dark details.
- Better low-light sensitivity: Larger pixels means good image quality even under poor lighting.
- Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
- 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.
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.70x).
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Longer lasting: Gets more shots (610 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 (3.1 vs 2.0).
- Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
- 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).
If the number of relative strengths (bullet points above) is taken as a guide, the A7 III is the clear winner of the contest (17 : 7 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 sports photographer will view the differences between cameras in a way that diverges from the perspective of a street photog, and a person interested in family portraits has distinct needs from a landscape 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 A7 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 comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the GX9 or the A7 III. 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.
|Panasonic GX9||+||84/100||4.5/5||4.5/5||4.5/5||Feb 2018||849|
|Sony A7 III||+ +||89/100||5/5||5/5||5/5||Feb 2018||1,999|
|Canon M6||..||80/100||4/5||4.5/5||4/5||Feb 2017||779|
|Fujifilm X-E3||+||84/100||4.5/5||4.5/5||4.5/5||Sep 2017||899|
|Nikon Z6||..||..||4.5/5||4.5/5||5/5||Aug 2018||1,999|
|Olympus E-M10 IV||..||..||..||..||..||Aug 2020||699|
|Panasonic G90||+||83/100||4.5/5||4.5/5||4.5/5||Apr 2019||999|
|Panasonic LX100 II||+||82/100||4.5/5||4.5/5||4.5/5||Aug 2018||999|
|Panasonic TZ200||+ +||81/100||4.5/5||..||4.5/5||Feb 2018||799|
|Panasonic GH5||+ +||85/100||4.5/5||5/5||5/5||Jan 2017||1,999|
|Panasonic GX80||+ +||82/100||5/5||4.5/5||5/5||Apr 2016||799|
|Panasonic GX8||+||82/100||4.5/5||5/5||4.5/5||Jul 2015||1,199|
|Panasonic GX7||+||79/100||5/5||4.5/5||5/5||Aug 2013||999|
|Sony A9 II||..||90/100||5/5||..||5/5||Oct 2019||4,499|
|Sony A7R III||+ +||90/100||4.5/5||5/5||5/5||Oct 2017||3,199|
|Sony A9||+ +||89/100||5/5||5/5||5/5||Apr 2017||4,499|
|Sony A7 II||+||82/100||4.5/5||5/5||5/5||Nov 2014||1,999|
|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. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date 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? If you would like to see a different side-by-side camera review, 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.
- Canon 1100D vs Panasonic GX9
- Canon 5D Mark II vs Sony A7 III
- Canon SX620 vs Panasonic GX9
- Fujifilm X-M1 vs Sony A7 III
- Fujifilm X100 vs Panasonic GX9
- Fujifilm X20 vs Sony A7 III
- Nikon D5 vs Sony A7 III
- Nikon Df vs Panasonic GX9
- Olympus E-PL3 vs Sony A7 III
- Panasonic GH1 vs Panasonic GX9
- Panasonic GX9 vs Sony A7R II
- Pentax KP vs Sony A7 III
Specifications: Panasonic GX9 vs Sony A7 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 A7 III|
|Camera Type||Mirrorless system camera||Mirrorless system camera|
|Camera Lens||Micro Four Thirds lenses||Sony E mount lenses|
|Launch Date||February 2018||February 2018|
|Launch Price||USD 849||USD 1,999|
|Sensor Specs||Panasonic GX9||Sony A7 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||24 Megapixels|
|Image Resolution||5184 x 3888 pixels||6000 x 4000 pixels|
|Pixel Pitch||3.34 μm||5.94 μm|
|Pixel Density||8.96 MP/cm2||2.83 MP/cm2|
|Moiré control||no AA filter||Anti-Alias filter|
|Movie Capability||4K/30p Video||4K/30p Video|
|ISO Setting||200 - 25,600 ISO||100 - 51,200 ISO|
|ISO Boost||100 - 25,600 ISO||50 - 204,800 ISO|
|Image Processor||Venus||BIONZ X|
|DXO Sensor Quality (score)||..||96|
|DXO Color Depth (bits)||..||25.0|
|DXO Dynamic Range (EV)||..||14.7|
|DXO Low Light (ISO)||..||3730|
|Screen Specs||Panasonic GX9||Sony A7 III|
|Viewfinder Type||Electronic viewfinder||Electronic viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||2760k dots||2359k dots|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||1240k dots||922k dots|
|LCD Attachment||Tilting screen||Tilting screen|
|Shooting Specs||Panasonic GX9||Sony A7 III|
|Focus System||Contrast-detect AF||On-Sensor Phase-detect|
|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||Intervalometer built-in|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||Build-in Flash||no On-Board Flash|
|Storage Medium||SDXC cards||MS or SDXC cards|
|Second Storage Option||Single card slot||Dual card slots|
|UHS card support||UHS-I||Single UHS-II|
|Connectivity Specs||Panasonic GX9||Sony A7 III|
|USB Connector||USB 2.0||USB 3.1|
|HDMI Port||micro HDMI||micro HDMI|
|Microphone Port||no MIC socket||External MIC port|
|Headphone Socket||no Headphone port||Headphone port|
|Wifi Support||Wifi built-in||Wifi built-in|
|Near-Field Communication||no NFC||NFC built-in|
|Bluetooth Support||Bluetooth built-in||Bluetooth built-in|
|Body Specs||Panasonic GX9||Sony A7 III|
|Environmental Sealing||not weather sealed||Weathersealed body|
|Battery Life (CIPA)||260 shots per charge||610 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 96 x 74 mm
(5.0 x 3.8 x 2.9 in)
|Camera Weight||407 g (14.4 oz)||650 g (22.9 oz)|
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