Panasonic G9 II vs Sony A7 III

The Panasonic Lumix DC-G9 II and the Sony Alpha A7 III are two enthusiast cameras that were revealed to the public, respectively, in September 2023 and February 2018. Both the G9 II and the A7 III are mirrorless interchangeable lens cameras that are based on a Four Thirds (G9 II) and a full frame (A7 III) sensor. The Panasonic has a resolution of 25 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.

Headline Specifications

Panasonic G9 II		Sony A7 III
Mirrorless system camera		Mirrorless system camera
Micro Four Thirds lenses		Sony E mount lenses
25 MP – Four Thirds sensor		24 MP – Full Frame sensor
5.7K/60p Video		4K/30p Video
ISO 100-25,600		ISO 100-51,200 (50 - 204,800)
Electronic viewfinder (3680k dots)		Electronic viewfinder (2359k dots)
3.0" LCD – 1840k dots		3.0" LCD – 922k dots
Swivel touchscreen		Tilting touchscreen
10 shutter flaps per second		10 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		Weathersealed body
390 shots per battery charge		610 shots per battery charge
134 x 102 x 90 mm, 658 g		127 x 96 x 74 mm, 650 g

Check G9 II price at
amazon.com
Check A7 III price at
amazon.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Panasonic Lumix DC-G9 II 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.

Body comparison

An illustration of the physical size and weight of the Panasonic G9 II and the Sony A7 III is provided 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 size dimensions are rounded to the nearest millimeter.

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 smaller (11 percent) than the Panasonic G9 II. Moreover, the A7 III is slightly lighter (1 percent) than the G9 II. 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 compare the optics available for the two cameras in the Micro Four Thirds Lens Catalog (G9 II) 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 G9 II gets 390 shots out of its Panasonic DMW-BLK22 battery, while the A7 III can take 610 images on a single charge of its Sony 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 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.

Body Specifications

		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price	Street Price
1.		Panasonic G9 II	134 mm	102 mm	90 mm	658 g	390	Y	Sep 2023	US$ 1 899	amazon.com
2.		Sony A7 III	127 mm	96 mm	74 mm	650 g	610	Y	Feb 2018	US$ 1 999	amazon.com
3.		Nikon Z6	134 mm	101 mm	67 mm	675 g	310	Y	Aug 2018	US$ 1 999	ebay.com
4.		Nikon Zf	144 mm	103 mm	49 mm	710 g	380	Y	Sep 2023	US$ 1 999	amazon.com
5.		Olympus E-M1 II	134 mm	91 mm	67 mm	574 g	440	Y	Sep 2016	US$ 1 999	ebay.com
6.		Olympus E-M1 III	134 mm	91 mm	69 mm	580 g	420	Y	Feb 2020	US$ 1 799	ebay.com
7.		OM System OM-1	135 mm	92 mm	73 mm	599 g	520	Y	Feb 2022	US$ 2 199	ebay.com
8.		Panasonic G9	137 mm	97 mm	92 mm	658 g	400	Y	Nov 2017	US$ 1 699	ebay.com
9.		Panasonic GH5	139 mm	98 mm	87 mm	725 g	410	Y	Jan 2017	US$ 1 999	ebay.com
10.		Panasonic GH5 II	139 mm	98 mm	87 mm	727 g	400	Y	May 2021	US$ 1 699	amazon.com
11.		Panasonic GH6	138 mm	100 mm	100 mm	823 g	360	Y	Feb 2022	US$ 2 199	amazon.com
12.		Panasonic S5	133 mm	98 mm	82 mm	714 g	440	Y	Sep 2020	US$ 1 999	amazon.com
13.		Panasonic S5 II	134 mm	102 mm	90 mm	740 g	370	Y	Jan 2023	US$ 1 999	amazon.com
14.		Sony A7 II	127 mm	96 mm	60 mm	599 g	350	Y	Nov 2014	US$ 1 999	ebay.com
15.		Sony A7R III	127 mm	96 mm	74 mm	650 g	650	Y	Oct 2017	US$ 3 199	ebay.com
16.		Sony A7R IV	129 mm	96 mm	78 mm	665 g	670	Y	Jul 2019	US$ 3 499	ebay.com
17.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	US$ 4 499	ebay.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
Convert to Imperial

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 G9 II was somewhat cheaper (by 5 percent) than the A7 III 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.

Sensor comparison

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 G9 II 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 G9 II has a native 4:3 aspect ratio, while the one in the A7 III offers a 3:2 aspect.

Despite having a smaller sensor, the Panasonic G9 II offers a higher resolution of 25 megapixels, compared with 24 MP of the Sony A7 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 3.00μm versus 5.94μm for the A7 III). However, it should be noted that the G9 II is much more recent (by 5 years and 6 months) than the A7 III, and its sensor will have benefitted from technological advances during this time that make it possible to gather light more efficiently. Coming back to sensor resolution, it should be mentioned that the G9 II has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

Unlike the A7 III, the G9 II has the capacity to capture high quality composite images (100MP) 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).

The Panasonic Lumix DC-G9 II has a native sensitivity range from ISO 100 to ISO 25600, which can be extended to ISO 50-25600. 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.

In terms of underlying technology, the G9 II is build around a CMOS sensor, while the A7 III uses a BSI-CMOS imager. Both cameras use a Bayer filter for capturing RGB colors on a square grid of photosensors. This arrangement is found in most digital cameras.

Consistent information on actual sensor performance is available from DXO Mark for many cameras. 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 adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.

Sensor Characteristics

		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Panasonic G9 II	Four Thirds	25.0	5776	4336	5.7K/60p	23.4	13.5	1710	78
2.		Sony A7 III	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3730	96
3.		Nikon Z6	Full Frame	24.3	6048	4024	4K/30p	25.3	14.3	3299	95
4.		Nikon Zf	Full Frame	24.3	6048	4024	4K/60p	25.4	14.7	3243	96
5.		Olympus E-M1 II	Four Thirds	20.2	5184	3888	4K/30p	23.7	12.8	1312	80
6.		Olympus E-M1 III	Four Thirds	20.2	5184	3888	4K/30p	23.3	13.1	1356	76
7.		OM System OM-1	Four Thirds	20.2	5184	3888	4K/60p	23.4	13.4	1553	77
8.		Panasonic G9	Four Thirds	20.2	5184	3888	4K/60p	23.1	12.8	1138	74
9.		Panasonic GH5	Four Thirds	20.2	5184	3888	4K/60p	23.9	13.0	807	77
10.		Panasonic GH5 II	Four Thirds	20.2	5184	3888	4K/60p	23.7	13.1	1136	79
11.		Panasonic GH6	Four Thirds	25.0	5776	4336	5.7K/60p	23.4	13.4	1555	77
12.		Panasonic S5	Full Frame	24.0	6000	4000	4K/60p	25.1	14.5	2697	94
13.		Panasonic S5 II	Full Frame	24.0	6000	4000	6K/30p	25.4	14.6	3158	96
14.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
15.		Sony A7R III	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
16.		Sony A7R IV	Full Frame	60.2	9504	6336	4K/30p	26.0	14.8	3344	99
17.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
Note: DXO values in italics represent estimates based on sensor size and age.

Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the G9 II provides a higher video resolution than the A7 III. It can shoot video footage at 5.7K/60p, while the Sony is limited to 4K/30p.

Feature comparison

Apart from 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 G9 II offers a substantially higher resolution than the one in the A7 III (3680k vs 2359k dots). The following table reports on some other key feature differences and similarities of the Panasonic G9 II, the Sony A7 III, and comparable cameras.

Core Features

		Camera Model	Viewfinder (Type or 000 dots)	Control Panel (yes/no)	LCD Specifications (inch/000 dots)	LCD Attach- ment	Touch Screen (yes/no)	Max Shutter Speed *	Max Shutter Flaps *	Built-in Flash (yes/no)	Built-in Image Stab
1.		Panasonic G9 II	3680	n	3.0 / 1840	swivel	Y	1/8000s	10.0/s	n	Y
2.		Sony A7 III	2359	n	3.0 / 922	tilting	Y	1/8000s	10.0/s	n	Y
3.		Nikon Z6	3690	Y	3.2 / 2100	tilting	Y	1/8000s	12.0/s	n	Y
4.		Nikon Zf	3690	n	3.2 / 2100	swivel	Y	1/8000s	14.0/s	n	Y
5.		Olympus E-M1 II	2360	n	3.0 / 1037	swivel	Y	1/8000s	18.0/s	n	Y
6.		Olympus E-M1 III	2360	n	3.0 / 1037	swivel	Y	1/8000s	18.0/s	n	Y
7.		OM System OM-1	5760	n	3.0 / 1640	swivel	Y	1/8000s	10.0/s	n	Y
8.		Panasonic G9	3680	Y	3.0 / 1040	swivel	Y	1/8000s	20.0/s	n	Y
9.		Panasonic GH5	3680	n	3.2 / 1620	swivel	Y	1/8000s	12.0/s	n	Y
10.		Panasonic GH5 II	3680	n	3.0 / 1840	swivel	Y	1/8000s	12.0/s	n	Y
11.		Panasonic GH6	3680	n	3.0 / 1840	full-flex	Y	1/8000s	14.0/s	n	Y
12.		Panasonic S5	2360	n	3.0 / 1840	swivel	Y	1/8000s	7.0/s	n	Y
13.		Panasonic S5 II	3680	n	3.0 / 1840	swivel	Y	1/8000s	9.0/s	n	Y
14.		Sony A7 II	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	Y
15.		Sony A7R III	3686	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
16.		Sony A7R IV	5760	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
17.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

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 G9 II 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 G9 II writes its imaging data to SDXC cards, while the A7 III uses SDXC or Memory Stick PRO Duo cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. However, while the G9 II supports UHS-II cards (Ultra High Speed data transfer of up to 312 MB/s) on both slots, the A7 III supports UHS-II only on its first slot and UHS-I (data transfer speed up to 104 MB/s) on the second one.

Connectivity comparison

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-G9 II and Sony Alpha A7 III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.

Input-Output Connections

		Camera Model	Hotshoe Port	Internal Mic / Speaker	Microphone Port	Headphone Port	HDMI Port	USB Port	WiFi Support	NFC Support	Bluetooth Support
1.		Panasonic G9 II	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
2.		Sony A7 III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
3.		Nikon Z6	Y	stereo / mono	Y	Y	micro	3.1	Y	-	Y
4.		Nikon Zf	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
5.		Olympus E-M1 II	Y	stereo / mono	Y	Y	micro	3.0	Y	-	-
6.		Olympus E-M1 III	Y	stereo / mono	Y	Y	micro	3.1	Y	-	Y
7.		OM System OM-1	Y	stereo / mono	Y	Y	micro	3.0	Y	-	Y
8.		Panasonic G9	Y	stereo / mono	Y	Y	full	3.0	Y	-	Y
9.		Panasonic GH5	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
10.		Panasonic GH5 II	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
11.		Panasonic GH6	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
12.		Panasonic S5	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
13.		Panasonic S5 II	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
14.		Sony A7 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
15.		Sony A7R III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
16.		Sony A7R IV	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
17.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y

Both the G9 II and the A7 III are recent models that are part of the current product line-up. The A7 III replaced the earlier Sony A7 II, while the G9 II followed on from the Panasonic G9. Further information on the features and operation of the G9 II and A7 III can be found, respectively, in the Panasonic G9 II Manual (free pdf) or the online Sony A7 III Manual.

Review summary

So how do things add up? Which of the two cameras – the Panasonic G9 II or the Sony A7 III – has the upper hand? Is one clearly better than the other? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Panasonic Lumix DC-G9 II:

• 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 video: Provides higher definition movie capture (5.7K/60p vs 4K/30p).
• More detailed viewfinder: Has higher resolution electronic viewfinder (3680k vs 2359k dots).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.8x vs 0.78x).
• More detailed LCD: Has a higher resolution rear screen (1840k vs 922k 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 data transfer: Supports a more advanced USB protocol (3.2 vs 3.1).
• More solid recording: Has a full-sized HDMI port for a sturdy connection to an external recorder.
• More modern: Reflects 5 years and 6 months of technical progress since the A7 III launch.

Advantages of the Sony Alpha A7 III:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• More compact: Is smaller (127x96mm vs 134x102mm) and will fit more readily into a bag.
• Longer lasting: Gets more shots (610 versus 390) out of a single battery charge.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More heavily discounted: Has been around for much longer (launched in February 2018).

If the number of relative strengths (bullet points above) is taken as a guide, the G9 II is the clear winner of the match-up (11 : 5 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. A professional wildlife photographer will view the differences between cameras in a way that diverges from the perspective of a family photog, and a person interested in architecture has distinct needs from a sports 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 G9 II 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 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 G9 II 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.

Expert reviews

This is where reviews by experts come in. The table below provides a synthesis of the camera assessments of some of the best known photo-gear review sites (amateurphotographer [AP], cameralabs [CL], digitalcameraworld [DCW], 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.

Expert Camera Reviews

		Camera   Model	AP   score	CL   score	DCW   score	DPR   score	EPZ   score	PB   score	Camera Launch	Launch Price	Street Price
1.		Panasonic G9 II	5/5	..	4.5/5	87/100	..	4.5/5	Sep 2023	US$ 1 899	amazon.com
2.		Sony A7 III	..	+ +	4.5/5	89/100	5/5	5/5	Feb 2018	US$ 1 999	amazon.com
3.		Nikon Z6	5/5	..	5/5	89/100	4.5/5	5/5	Aug 2018	US$ 1 999	ebay.com
4.		Nikon Zf	4.5/5	..	4.5/5	90/100	4.5/5	5/5	Sep 2023	US$ 1 999	amazon.com
5.		Olympus E-M1 II	5/5	+ +	5/5	85/100	4.5/5	4.5/5	Sep 2016	US$ 1 999	ebay.com
6.		Olympus E-M1 III	5/5	..	5/5	83/100	4.5/5	4/5	Feb 2020	US$ 1 799	ebay.com
7.		OM System OM-1	5/5	..	..	87/100	5/5	4.5/5	Feb 2022	US$ 2 199	ebay.com
8.		Panasonic G9	..	+ +	5/5	85/100	5/5	5/5	Nov 2017	US$ 1 699	ebay.com
9.		Panasonic GH5	4.5/5	+ +	..	85/100	4.5/5	5/5	Jan 2017	US$ 1 999	ebay.com
10.		Panasonic GH5 II	4.5/5	..	4.5/5	85/100	4.5/5	5/5	May 2021	US$ 1 699	amazon.com
11.		Panasonic GH6	5/5	+ +	5/5	87/100	5/5	5/5	Feb 2022	US$ 2 199	amazon.com
12.		Panasonic S5	4.5/5	+ +	4.5/5	88/100	4.5/5	4.5/5	Sep 2020	US$ 1 999	amazon.com
13.		Panasonic S5 II	4.5/5	+ +	5/5	90/100	4.5/5	5/5	Jan 2023	US$ 1 999	amazon.com
14.		Sony A7 II	5/5	+	4/5	82/100	4.5/5	5/5	Nov 2014	US$ 1 999	ebay.com
15.		Sony A7R III	..	+ +	4/5	90/100	4.5/5	5/5	Oct 2017	US$ 3 199	ebay.com
16.		Sony A7R IV	5/5	+	4.5/5	91/100	4.5/5	5/5	Jul 2019	US$ 3 499	ebay.com
17.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	US$ 4 499	ebay.com
Note: (+ +) 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 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.

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Check A7 III price at
amazon.com

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. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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