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Sony A7R III versus Panasonic GX8

The Sony Alpha A7R III and the Panasonic Lumix DMC-GX8 are two enthusiast cameras that were announced, respectively, in October 2017 and July 2015. Both the A7R III and the GX8 are mirrorless interchangeable lens cameras that are based on a full frame (A7R III) and a Four Thirds (GX8) sensor. The Sony has a resolution of 42.2 megapixel, whereas the Panasonic provides 20.2 MP. Read on to find out how these two cameras compare with respect to their size, their sensors, their features, and their reception by expert reviewers.

Body comparison: Sony A7R III vs Panasonic GX8

The physical size and weight of the Sony A7R III and the Panasonic GX8 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. You can also use the toggle button to switch to a percentage comparison if you prefer that the measures are being expressed in relative terms (in this case, the camera on the left – the A7R III – represents the basis or 100 percent across all the size and weight measures).

Compare Sony A7R III vs Panasonic GX8
Compare A7R III versus GX8 top
Compare A7R III and GX8 rear

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Panasonic GX8 is notably smaller (15 percent) than the Sony A7R III. Moreover, the GX8 is markedly lighter (25 percent) than the A7R III. 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. A larger imaging sensor will tend to go along with bigger and heavier lenses, although exceptions exist. You can find an overview of optics for the two cameras in the Sony FE Lens Catalog (A7R III) and the Micro Four Thirds Lens Catalog (GX8). 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 A7R III gets 650 shots out of its NP-FZ100 battery, while the GX8 can take 330 images on a single charge of its DMW-BLC12 power pack.

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, just use the right or left arrows in the table to switch to the respective camera. Alternatively, you can also navigate to the CAM-parator app and make your selection from the full list of cameras there.

Camera Body Specifications
  Camera
Model
Camera
Width
Camera
Height
Camera
Depth
Camera
Weight
Battery
Life
(CIPA)
Weather
Sealing
(yes/no)
Camera
Launch
(announced)
Launch
Price
(USD)
Street
Price
(USD)
Used
Price
(USD)
Camera
Model
Sony A7R III» 5.0 in 3.8 in 2.9 in 22.9 oz 650 Y Oct 2017 3,199 i i Sony A7R III
Panasonic GX8« 5.2 in 3.1 in 2.5 in 17.2 oz 330 Y Jul 2015 1,199- i Panasonic GX8
Nikon Z7« » 5.3 in 4.0 in 2.6 in 23.8 oz 330 Y Aug 2018 3,399 i i Nikon Z7
Olympus E-M1 II« » 5.3 in 3.6 in 2.6 in 20.2 oz 440 Y Sep 2016 1,999 i i Olympus E-M1 II
Olympus PEN-F« » 4.9 in 2.8 in 1.5 in 15.1 oz 330 n Jan 2016 1,199 i i Olympus PEN-F
Olympus E-M5 II« » 4.9 in 3.3 in 1.8 in 16.5 oz 310 Y Feb 2015 1,099 i i Olympus E-M5 II
Olympus E-M1« » 5.1 in 3.7 in 2.5 in 17.5 oz 350 Y Sep 2013 1,399- i Olympus E-M1
Panasonic GX7« » 4.8 in 2.8 in 2.2 in 14.2 oz 350 n Aug 2013 999- i Panasonic GX7
Pentax K-1« » 5.4 in 4.3 in 3.4 in 35.6 oz 760 Y Feb 2016 1,799- i Pentax K-1
Sony A7 III« » 5.0 in 3.8 in 2.9 in 22.9 oz 610 Y Feb 2018 1,999 i i Sony A7 III
Sony A9« » 5.0 in 3.8 in 2.5 in 23.7 oz 650 Y Apr 2017 4,499 i i Sony A9
Sony A99 II« » 5.6 in 4.1 in 3.0 in 29.9 oz 490 Y Sep 2016 3,199 i i Sony A99 II
Sony A7R II« » 5.0 in 3.8 in 2.4 in 22.0 oz 290 Y Jun 2015 3,199- i Sony A7R II
Sony A7S II« » 5.0 in 3.8 in 2.4 in 22.1 oz 370 Y Sep 2015 2,999 i i Sony A7S II
Sony A7 II« » 5.0 in 3.8 in 2.4 in 21.1 oz 350 Y Nov 2014 1,999- i Sony A7 II
Sony A7R« » 5.0 in 3.7 in 1.9 in 16.4 oz 340 Y Oct 2013 2,299- i Sony A7R
Sony A99« » 5.8 in 4.4 in 3.1 in 28.6 oz 500 Y Sep 2012 2,799- i Sony A99

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 launched at a markedly lower price (by 63 percent) than the A7R 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.

 

Sensor comparison: Sony A7R III vs Panasonic GX8

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 Sony A7R III features a full frame sensor and the Panasonic GX8 a Four Thirds sensor. The sensor area in the GX8 is 74 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 2.0. The sensor in the A7R III has a native 3:2 aspect ratio, while the one in the GX8 offers a 4:3 aspect.

Sony A7R III and Panasonic GX8 sensor measures

With 42.2MP, the A7R III offers a higher resolution than the GX8 (20.2MP), but the A7R III nevertheless has larger individual pixels (pixel pitch of 4.52μm versus 3.34μm for the GX8) due to its larger sensor. Moreover, the A7R III is a somewhat more recent model (by 2 years and 3 months) than the GX8, 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 A7R III has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

Unlike the GX8, the A7R III 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).

A7R III versus GX8 MP

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. This service assesses and scores the color depth ("DXO Portrait"), dynamic range ("DXO Landscape"), and low-light sensitivity ("DXO Sports") of camera sensors, and also publishes an overall camera score. Of the two cameras under review, the A7R III provides substantially higher image quality than the GX8, with an overall score that is 25 points higher. This advantage is based on 2.5 bits higher color depth, 2.1 EV in additional dynamic range, and 2.1 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.

Sensor Characteristics
  Camera
Model
Sensor
Class
Resolution
(MP)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Camera
Model
Sony A7R III» Full Frame 42.2 7952 53044K/30p26.014.73523100Sony A7R III
Panasonic GX8« Four Thirds 20.2 5184 38884K/30p23.512.680675Panasonic GX8
Nikon Z7« » Full Frame 45.4 8256 55044K/30p----Nikon Z7
Olympus E-M1 II« » Four Thirds 20.2 5184 38884K/30p23.712.8131280Olympus E-M1 II
Olympus PEN-F« » Four Thirds 20.2 5184 38881080/60p23.112.489474Olympus PEN-F
Olympus E-M5 II« » Four Thirds 15.9 4608 34561080/60p23.012.584273Olympus E-M5 II
Olympus E-M1« » Four Thirds 15.9 4608 34561080/30p23.012.775773Olympus E-M1
Panasonic GX7« » Four Thirds 15.8 4592 34481080/60p22.612.271870Panasonic GX7
Pentax K-1« » Full Frame 36.2 7360 49121080/60i25.414.6328096Pentax K-1
Sony A7 III« » Full Frame 24.0 6000 40004K/30p25.014.7373096Sony A7 III
Sony A9« » Full Frame 24.0 6000 40004K/30p24.913.3351792Sony A9
Sony A99 II« » Full Frame 42.2 7952 53044K/30p25.413.4231792Sony A99 II
Sony A7R II« » Full Frame 42.2 7952 53044K/30p26.013.9343498Sony A7R II
Sony A7S II« » Full Frame 12.0 4240 28324K/30p23.613.3299385Sony A7S II
Sony A7 II« » Full Frame 24.0 6000 40001080/60p24.913.6244990Sony A7 II
Sony A7R« » Full Frame 36.2 7360 49121080/60p25.614.1274695Sony A7R
Sony A99« » Full Frame 24.0 6000 40001080/60p25.014.0155589Sony A99

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, and both provide the same movie specifications (4K/30p).

 

Feature comparison: Sony A7R III vs Panasonic GX8

Beyond body and sensor, cameras can and do differ across a range of features. The two cameras under consideration are similar with respect to both having an electronic viewfinder. However, the one in the A7R III offers a substantially higher resolution than the one in the GX8 (3686k vs 2360k dots). The adjacent table lists some of the other core features of the Sony A7R III and Panasonic GX8 along with similar information for a selection of comparators. If you need more detail on the specs, you can find comprehensive listings, for example, in the dpreview camera hub.

Core Features
  Camera
Model
Viewfinder
(Type or
'000 dots)
Control
Panel
(yes/no)
LCD
Size
(inch)
LCD
Resolution
('000 dots)
LCD
Attach-
ment
Touch
Screen
(yes/no)
Shutter
speed
(1/sec)
Shutter
flaps
(1/sec)
Build-in
Flash
(yes/no)
Build-in
Image
Stab
Camera
Model
Sony A7R III»3686 n 3.0 1440 tilting Y 8000 10.0 n Y Sony A7R III
Panasonic GX8«2360 n 3.0 1040 swivel Y 8000 10.0 n Y Panasonic GX8
Nikon Z7« »3690 Y 3.2 2100 tilting Y 8000 9.0 n Y Nikon Z7
Olympus E-M1 II« »2360 n 3.0 1037 swivel Y 8000 18.0 n Y Olympus E-M1 II
Olympus PEN-F« »2360 n 3.0 1037 swivel Y 8000 10.0 n Y Olympus PEN-F
Olympus E-M5 II« »2360 n 3.0 1037 swivel Y 8000 10.0 n Y Olympus E-M5 II
Olympus E-M1« »2360 n 3.0 1037 tilting Y 8000 10.0 n Y Olympus E-M1
Panasonic GX7« »2760 n 3.0 1040 tilting Y 8000 5.0 Y Y Panasonic GX7
Pentax K-1« »optical Y 3.2 1037 full-flex n 8000 4.4 n Y Pentax K-1
Sony A7 III« »2359 n 3.0 922 tilting Y 8000 10.0 n Y Sony A7 III
Sony A9« »3686 n 3.0 1440 tilting Y 8000 20.0 n Y Sony A9
Sony A99 II« »2400 Y 3.0 1229 full-flex n 8000 12.0 n Y Sony A99 II
Sony A7R II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7R II
Sony A7S II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7S II
Sony A7 II« »2400 n 3.0 1230 tilting n 8000 5.0 n Y Sony A7 II
Sony A7R« »2400 n 3.0 1230 tilting n 8000 4.0 n n Sony A7R
Sony A99« »2359 Y 3.0 1229 full-flex n 8000 6.0 n Y Sony A99

The reported shutter speed and shutter burst refer to the use of the mechanical shutter. In addition, both cameras feature an electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (rolling shutter) or shooting under artificial light sources (flickering).

The A7R III writes its imaging data to SDXC or Memory Stick PRO Duo cards, while the GX8 uses SDXC cards. The A7R III features dual card slots, which can be very useful in case a memory card fails. In contrast, the GX8 only has one slot.

Input-Output Connections
  Camera
Model
Hotshoe
Port
Internal
Microphone
Internal
Speaker
Microphone
Port
Headphone
Port
HDMI
Port
USB
Type
WiFi
Support
NFC
Support
Bluetooth
Support
Camera
Model
Sony A7R III»YstereomonoYYmicro3.1YYYSony A7R III
Panasonic GX8«YstereomonoY-micro2.0YY-Panasonic GX8
Nikon Z7« »YstereomonoYYmicro3.1Y-YNikon Z7
Olympus E-M1 II« »YstereomonoYYmicro3.0Y--Olympus E-M1 II
Olympus PEN-F« »Ystereomono--micro2.0Y--Olympus PEN-F
Olympus E-M5 II« »YstereomonoY-micro2.0Y--Olympus E-M5 II
Olympus E-M1« »YstereomonoY-micro2.0Y--Olympus E-M1
Panasonic GX7« »Ystereomono--mini2.0YY-Panasonic GX7
Pentax K-1« »YstereomonoYYmicro2.0Y--Pentax K-1
Sony A7 III« »YstereomonoYYmicro3.1YYYSony A7 III
Sony A9« »YstereomonoYYmicro2.0YYYSony A9
Sony A99 II« »YstereomonoYYmicro2.0YYYSony A99 II
Sony A7R II« »YstereomonoYYmicro2.0YY-Sony A7R II
Sony A7S II« »YstereomonoYYmicro2.0YY-Sony A7S II
Sony A7 II« »YstereomonoYYmicro2.0YY-Sony A7 II
Sony A7R« »YstereomonoYYmicro2.0YY-Sony A7R
Sony A99« »YstereomonoYYmini2.0---Sony A99

The A7R III is a current model that online retailers, such as amazon, will have in stock. In contrast, the GX8 has been discontinued (but it can be found pre-owned on eBay). As a replacement in the same line of cameras, the GX8 was succeeded by the Panasonic GX9.

Review summary: Sony A7R III vs Panasonic GX8

So what is the bottom line? Is the Sony A7R III better than the Panasonic GX8 or vice versa? A synthesis of the relative strong points of each of the models is listed below.

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Advantages of the Sony Alpha A7R III:

  • More detail: Offers more megapixels (42.2 vs 20.2MP) with a 48% 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 (25 points) in the DXO overall assessment.
  • Richer colors: Generates images with noticeably better colors (2.5 bits more color depth).
  • More dynamic range: Captures a larger spectrum of light and dark details (2.1 EV of extra DR).
  • Better low-light sensitivity: Requires less light for good images (2.1 stops ISO advantage).
  • Better sound control: Has a headphone port that enables audio monitoring while recording.
  • More detailed viewfinder: Has higher resolution electronic viewfinder (3686k vs 2360k dots).
  • More detailed LCD: Has a higher resolution rear screen (1440k vs 1040k dots).
  • Longer lasting: Can take more shots (650 versus 330) on a single battery charge.
  • Faster data transfer: Supports a more advanced USB protocol (3.1 vs 2.0).
  • Easier wireless transfer: Supports Bluetooth for image sharing without cables.
  • Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
  • More modern: Reflects 2 years and 3 months of technical progress since the GX8 launch.

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Arguments in favor of the Panasonic Lumix DMC-GX8:

  • Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
  • More flexible LCD: Has swivel screen for odd-angle shots in portrait or landscape orientation.
  • More compact: Is smaller (133x78mm vs 127x96mm) and will fit more readily into a bag.
  • Less heavy: Has a lower weight (by 163g or 25 percent) and is thus easier to take along.
  • More affordable: Was introduced into a lower priced category (63 percent cheaper at launch).
  • More heavily discounted: Has been around for much longer (launched in July 2015).

If the count of individual advantages (bullet points above) is taken as a guide, the A7R III is the clear winner of the match-up (15 : 6 points). 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.

A7R III 15:06 GX8

In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it says nothing about, for example, the handling, responsiveness, and overall imaging quality of the A7R III and the GX8 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 table relays the overall verdicts of several of the most popular camera review sites (cameralabs, dpreview, ephotozine, imaging-resource, photographyblog). The detailed reviews can be accessed by clicking on the site logo in the table header.

Review Scores
  Camera
Model
cameralabs dpreview ephotozine imaging-resource photographyblog Camera
Launch
(announced)
Launch
Price
(USD)
Street
Price
(USD)
Used
Price
(USD)
Camera
Model
Sony A7R III»HiRec90/1004.5/55/55/5 Oct 2017 3,199 i i Sony A7R III
Panasonic GX8«Rec82/1004.5/55/54.5/5 Jul 2015 1,199- i Panasonic GX8
Nikon Z7« »--4.5/5-5/5 Aug 2018 3,399 i i Nikon Z7
Olympus E-M1 II« »HiRec85/1004.5/55/54.5/5 Sep 2016 1,999 i i Olympus E-M1 II
Olympus PEN-F« »-82/1004.5/54.5/55/5 Jan 2016 1,199 i i Olympus PEN-F
Olympus E-M5 II« »HiRec81/1005/54.5/55/5 Feb 2015 1,099 i i Olympus E-M5 II
Olympus E-M1« »HiRec84/1004.5/54.5/54.5/5 Sep 2013 1,399- i Olympus E-M1
Panasonic GX7« »Rec79/1005/54.5/55/5 Aug 2013 999- i Panasonic GX7
Pentax K-1« »-84/1005/54.5/55/5 Feb 2016 1,799- i Pentax K-1
Sony A7 III« »HiRec89/1005/55/55/5 Feb 2018 1,999 i i Sony A7 III
Sony A9« »HiRec89/1005/55/55/5 Apr 2017 4,499 i i Sony A9
Sony A99 II« »-85/1004.5/54.5/54.5/5 Sep 2016 3,199 i i Sony A99 II
Sony A7R II« »HiRec90/1005/54.5/55/5 Jun 2015 3,199- i Sony A7R II
Sony A7S II« »Rec-4.5/55/55/5 Sep 2015 2,999 i i Sony A7S II
Sony A7 II« »Rec82/1004.5/55/55/5 Nov 2014 1,999- i Sony A7 II
Sony A7R« »HiRec82/1004.5/55/55/5 Oct 2013 2,299- i Sony A7R
Sony A99« »-84/1004.5/5rev4.5/5 Sep 2012 2,799- i Sony A99

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. An an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool. If the camera you are interested in is not available, please contact me, and I will try to update the database with the necessary infos.

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