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Panasonic GM1 versus Sony A7 III

The Panasonic Lumix DMC-GM1 and the Sony Alpha A7 III are two digital cameras that were announced, respectively, in October 2013 and February 2018. Both the GM1 and the A7 III are mirrorless interchangeable lens cameras that are based on a Four Thirds (GM1) and a full frame (A7 III) sensor. The Panasonic has a resolution of 15.8 megapixel, whereas the Sony provides 24 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: Panasonic GM1 vs Sony A7 III

The physical size and weight of the Panasonic GM1 and the Sony A7 III are illustrated in the side-by-side display below. 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 dimensions are rounded to the nearest millimeter. You can also toggle the display 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 side – the GM1 – represents the basis for the calculations across all the size and weight measures).

Compare Panasonic GM1 vs Sony A7 III
Compare GM1 versus A7 III top
Compare GM1 and A7 III rear

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 considerably larger (124 percent) than the Panasonic GM1. Moreover, the A7 III is substantially heavier (219 percent) than the GM1. It is noteworthy in this context that the A7 III is splash and dust-proof, while the GM1 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 find an overview of optics for the two cameras in the Micro Four Thirds Lens Catalog (GM1) 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 GM1 gets 230 shots out of its DMW-BLH7 battery, while the A7 III can take 610 images on a single charge of its NP-FZ100 power pack.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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
Panasonic GM1» 3.9 in 2.2 in 1.2 in 7.2 oz 230 n Oct 2013 749- i Panasonic GM1
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
Panasonic GM5« » 3.9 in 2.4 in 1.4 in 7.4 oz 220 n Sep 2014 749- i Panasonic GM5
Panasonic LX100« » 4.5 in 2.6 in 2.2 in 13.9 oz 300 n Sep 2014 899 i i Panasonic LX100
Panasonic G6« » 4.8 in 3.3 in 2.8 in 13.8 oz 340 n Apr 2013 599- i Panasonic G6
Panasonic GF6« » 4.4 in 2.6 in 1.5 in 11.4 oz 340 n Apr 2013 499- i Panasonic GF6
Panasonic GX7« » 4.8 in 2.8 in 2.2 in 14.2 oz 350 n Aug 2013 999- i Panasonic GX7
Panasonic G5« » 4.7 in 3.3 in 2.8 in 14.0 oz 320 n Jul 2012 599- i Panasonic G5
Panasonic GF5« » 4.3 in 2.6 in 1.5 in 9.4 oz 360 n Apr 2012 499- i Panasonic GF5
Panasonic GH3« » 5.2 in 3.7 in 3.2 in 19.4 oz 540 Y Sep 2012 1,299- i Panasonic GH3
Panasonic G3« » 4.5 in 3.3 in 1.9 in 11.9 oz 270 n May 2011 599- i Panasonic G3
Ricoh GR« » 4.6 in 2.4 in 1.4 in 8.6 oz 290 n Apr 2013 799- i Ricoh GR
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 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 A7« » 5.0 in 3.7 in 1.9 in 16.7 oz 340 Y Oct 2013 1,699- i Sony A7

The camera’s price is obviously a critical decision-making factor. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The GM1 was launched at a markedly lower price (by 63 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.

 

Sensor comparison: Panasonic GM1 vs Sony A7 III

The size of the imaging sensor is a crucial determinant 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 tend to be more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Panasonic GM1 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 GM1 has a native 4:3 aspect ratio, while the one in the A7 III offers a 3:2 aspect.

Panasonic GM1 and Sony A7 III sensor measures

With 24MP, the A7 III offers a higher resolution than the GM1 (15.8MP), but the A7 III nevertheless has larger individual pixels (pixel pitch of 5.94μm versus 3.77μm for the GM1) due to its larger sensor. Moreover, the A7 III is a much more recent model (by 4 years and 4 months) than the GM1, 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 A7 III has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The A7 III has on-sensor phase detect pixels, which results in relatively fast and reliable autofocus acquisition during video recording.

GM1 versus A7 III MP

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 consideration, the A7 III offers substantially better image quality than the GM1 (overall score 30 points higher). The advantage is based on 2.7 bits higher color depth, 3 EV in additional dynamic range, and 2.5 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
Panasonic GM1» Four Thirds 15.8 4592 34481080/60i22.311.766066Panasonic GM1
Sony A7 III« Full Frame 24.0 6000 40004K/30p25.014.7373096Sony A7 III
Panasonic GM5« » Four Thirds 15.8 4592 34481080/60p22.111.772166Panasonic GM5
Panasonic LX100« » Four Thirds 12.7 4112 30884K/30p22.312.555367Panasonic LX100
Panasonic G6« » Four Thirds 15.9 4608 34561080/60p21.311.563961Panasonic G6
Panasonic GF6« » Four Thirds 15.8 4592 34481080/60i20.710.662254Panasonic GF6
Panasonic GX7« » Four Thirds 15.8 4592 34481080/60p22.612.271870Panasonic GX7
Panasonic G5« » Four Thirds 15.9 4608 34561080/60p----Panasonic G5
Panasonic GF5« » Four Thirds 12.0 4000 30001080/60i21.411.661861Panasonic GF5
Panasonic GH3« » Four Thirds 15.9 4608 34561080/60p22.712.481271Panasonic GH3
Panasonic G3« » Four Thirds 15.8 4592 34481080/60i21.010.666756Panasonic G3
Ricoh GR« » APS-C 16.1 4928 32641080/30p23.613.597278Ricoh GR
Sony A9« » Full Frame 24.0 6000 40004K/30p24.913.3351792Sony A9
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 A7« » Full Frame 24.0 6000 40001080/60p24.814.2224890Sony A7

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 A7 III provides a better video resolution than the GM1. It can shoot movie footage at 4K/30p, while the Panasonic is limited to 1080/60i.

 

Feature comparison: Panasonic GM1 vs Sony A7 III

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the A7 III has an electronic viewfinder (2359k dots), which can be very helpful when shooting in bright sunlight. In contrast, the GM1 relies on live view and the rear LCD for framing. The following table reports on some other key feature differences and similarities of the Panasonic GM1, the Sony A7 III, and comparable cameras. If needed, the dpreview camera hub, for example, contains further detail on the cameras' specs.

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
Panasonic GM1»- n 3.0 1036 fixed Y 500 5.0 Y n Panasonic GM1
Sony A7 III«2359 n 3.0 922 tilting Y 8000 10.0 n Y Sony A7 III
Panasonic GM5« »1166 n 3.0 921 fixed Y 500 5.8 n n Panasonic GM5
Panasonic LX100« »2764 n 3.0 921 fixed n 4000 11.0 n Y Panasonic LX100
Panasonic G6« »1440 n 3.0 1036 swivel Y 4000 7.0 Y n Panasonic G6
Panasonic GF6« »- n 3.0 1040 tilting Y 4000 4.2 Y n Panasonic GF6
Panasonic GX7« »2760 n 3.0 1040 tilting Y 8000 5.0 Y Y Panasonic GX7
Panasonic G5« »1440 n 3.0 920 swivel Y 4000 6.0 Y n Panasonic G5
Panasonic GF5« »- n 3.0 920 fixed Y 4000 4.0 Y n Panasonic GF5
Panasonic GH3« »1746 n 3.0 614 swivel Y 4000 6.0 Y n Panasonic GH3
Panasonic G3« »1440 n 3.0 460 swivel Y 4000 4.0 Y n Panasonic G3
Ricoh GR« »- n 3.0 1230 fixed n 4000 4.0 Y n Ricoh GR
Sony A9« »3686 n 3.0 1440 tilting Y 8000 20.0 n Y Sony A9
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 A7« »2400 n 3.0 1230 tilting n 8000 5.0 n n Sony A7

One difference between the cameras concerns the presence of an on-board flash. The GM1 has one, while the A7 III does not. While the build-in flash of the GM1 is not very powerful, it can at times be useful as a fill-in light.

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 GM1 writes its imaging data to SDXC cards, while the A7 III uses SDXC or Memory Stick PRO Duo cards.

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
Panasonic GM1»-stereomono--micro2.0Y--Panasonic GM1
Sony A7 III«YstereomonoYYmicro3.1YYYSony A7 III
Panasonic GM5« »Ystereomono--micro2.0Y--Panasonic GM5
Panasonic LX100« »Ystereomono--micro2.0YY-Panasonic LX100
Panasonic G6« »YstereomonoY-mini2.0YY-Panasonic G6
Panasonic GF6« »-stereomono--mini2.0YY-Panasonic GF6
Panasonic GX7« »Ystereomono--mini2.0YY-Panasonic GX7
Panasonic G5« »Ystereomono--mini2.0---Panasonic G5
Panasonic GF5« »-stereomono--mini2.0---Panasonic GF5
Panasonic GH3« »YstereomonoYYmini2.0Y--Panasonic GH3
Panasonic G3« »Ystereomono--mini2.0---Panasonic G3
Ricoh GR« »Ymonomono--micro2.0---Ricoh GR
Sony A9« »YstereomonoYYmicro2.0YYYSony A9
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 A7« »YstereomonoYYmicro2.0YY-Sony A7

The A7 III is a recent model that features in the current product line-up of Sony. In contrast, the GM1 has been discontinued (but it can be found pre-owned on eBay). As a replacement in the same line of cameras, the GM1 was succeeded by the Panasonic GM5.

Review summary: Panasonic GM1 vs Sony A7 III

So what is the bottom line? Is there a clear favorite between the Panasonic GM1 and the Sony A7 III? A synthesis of the relative strong points of each of the models is listed below.

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Reasons to prefer the Panasonic Lumix DMC-GM1:

  • Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
  • More detailed LCD: Has a higher resolution rear screen (1036k vs 922k dots).
  • More compact: Is smaller (99x55mm vs 127x96mm) and thus needs less room in the bag.
  • Less heavy: Is lighter (by 446g or 69 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 (63 percent cheaper at launch).
  • More heavily discounted: Has been available for much longer (launched in October 2013).

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Arguments in favor of the Sony Alpha A7 III:

  • More detail: Has more megapixels (24 vs 15.8MP), which boosts linear resolution by 26%.
  • Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
  • Better image quality: Scores substantially higher (30 points) in the DXO overall evaluation.
  • Richer colors: Generates noticeably more natural colors (2.7 bits more color depth).
  • More dynamic range: Captures a broader range of light and dark details (3 EV of extra DR).
  • Better low-light sensitivity: Can shoot in dim conditions (2.5 stops ISO advantage).
  • Better video: Provides higher definition movie capture (4K/30p vs 1080/60i).
  • Better video autofocus: Features on-sensor phase-detection for more confident movie 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.
  • Easier framing: Has an electronic viewfinder for image framing and settings control.
  • More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
  • Faster shutter: Has higher mechanical shutter speed (8000/sec vs 500/sec) to freeze action.
  • Faster burst: Shoots at higher frequency (10 vs 5 flaps/sec) to capture the decisive moment.
  • Longer lasting: Gets more shots (610 versus 230) out of a single battery charge.
  • Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
  • Sharper images: Has stabilization technology build-in to reduce the impact of hand-shake.
  • Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
  • 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.
  • Easier wireless transfer: Supports Bluetooth for image sharing without cables.
  • More modern: Reflects 4 years and 4 months of technical progress since the GM1 launch.

If the count of individual advantages (bullet points above) is taken as a guide, the A7 III is the clear winner of the contest (22 : 7 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features before making a decision on a new camera.

GM1 07:22 A7 III

In any case, while the specs-based evaluation of cameras is instructive in revealing their potential as photographic tools, it says nothing about, for example, the handling, responsiveness, and overall imaging quality of the GM1 and the A7 III in practical situations. At times, user reviews, such as those published at amazon, address these issues in a useful manner, but such feedback is on many occasions incomplete, inconsistent, and unreliable. This is where reviews by experts come in. The table below summarizes the assessments of some of the best known camera review sites (cameralabs, dpreview, ephotozine, imaging-resource, photographyblog). You can find the full text of the reviews 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
Panasonic GM1»Rec78/1005/54.5/54.5/5 Oct 2013 749- i Panasonic GM1
Sony A7 III«HiRec89/1005/55/55/5 Feb 2018 1,999 i i Sony A7 III
Panasonic GM5« »Rec77/1005/55/54.5/5 Sep 2014 749- i Panasonic GM5
Panasonic LX100« »HiRec85/1005/54/55/5 Sep 2014 899 i i Panasonic LX100
Panasonic G6« »HiRec-5/5-4.5/5 Apr 2013 599- i Panasonic G6
Panasonic GF6« »HiRec-4.5/5-4.5/5 Apr 2013 499- i Panasonic GF6
Panasonic GX7« »Rec79/1005/54.5/55/5 Aug 2013 999- i Panasonic GX7
Panasonic G5« »HiRec-4.5/54.5/54.5/5 Jul 2012 599- i Panasonic G5
Panasonic GF5« »--4.5/54/54.5/5 Apr 2012 499- i Panasonic GF5
Panasonic GH3« »HiRec79/1004.5/55/54.5/5 Sep 2012 1,299- i Panasonic GH3
Panasonic G3« »HiRec75/1004.5/54.5/55/5 May 2011 599- i Panasonic G3
Ricoh GR« »-79/1004.5/54.5/54.5/5 Apr 2013 799- i Ricoh GR
Sony A9« »HiRec89/1005/55/55/5 Apr 2017 4,499 i i Sony A9
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 A7« »HiRec80/1005/54.5/55/5 Oct 2013 1,699- i Sony A7

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. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, 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? In case you would like to check on the differences and similarities of other camera models, just make your choice using the following search menu. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting. If you cannot find the camera you are interested in, please send me an email, and I will try to locate and add the respective data to the application.

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