Panasonic G9 II vs Sony A9 III

The Panasonic Lumix DC-G9 II and the Sony Alpha A9 III are two digital cameras that were officially introduced, respectively, in September 2023 and November 2023. Both the G9 II and the A9 III are mirrorless interchangeable lens cameras that are based on a Four Thirds (G9 II) and a full frame (A9 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 A9 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/120p Video
ISO 100-25,600		ISO 250-25,600 (125 - 51,200)
Electronic viewfinder (3680k dots)		Electronic viewfinder (9440k dots)
3.0" LCD – 1840k dots		3.2" LCD – 2100k dots
Swivel touchscreen		Fully flexible touchscreen
10 shutter flaps per second		120 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		Weathersealed body
390 shots per battery charge		530 shots per battery charge
134 x 102 x 90 mm, 658 g		136 x 97 x 83 mm, 702 g

Check G9 II price at
amazon.com
Check A9 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 A9 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

The side-by-side display below illustrates the physical size and weight of the Panasonic G9 II and the Sony A9 III. 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 width, height and depth measures 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 A9 III is somewhat smaller (3 percent) than the Panasonic G9 II. However, the A9 III is markedly heavier (7 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 (A9 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 A9 III can take 530 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 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.

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 A9 III	136 mm	97 mm	83 mm	702 g	530	Y	Nov 2023	US$ 5 999	amazon.com
3.		Nikon Zf	144 mm	103 mm	49 mm	710 g	380	Y	Sep 2023	US$ 1 999	amazon.com
4.		Olympus E-M1 II	134 mm	91 mm	67 mm	574 g	440	Y	Sep 2016	US$ 1 999	ebay.com
5.		Olympus E-M1 III	134 mm	91 mm	69 mm	580 g	420	Y	Feb 2020	US$ 1 799	ebay.com
6.		OM System OM-1	135 mm	92 mm	73 mm	599 g	520	Y	Feb 2022	US$ 2 199	ebay.com
7.		Panasonic G9	137 mm	97 mm	92 mm	658 g	400	Y	Nov 2017	US$ 1 699	ebay.com
8.		Panasonic GH5	139 mm	98 mm	87 mm	725 g	410	Y	Jan 2017	US$ 1 999	ebay.com
9.		Panasonic GH5 II	139 mm	98 mm	87 mm	727 g	400	Y	May 2021	US$ 1 699	amazon.com
10.		Panasonic GH6	138 mm	100 mm	100 mm	823 g	360	Y	Feb 2022	US$ 2 199	amazon.com
11.		Panasonic S5	133 mm	98 mm	82 mm	714 g	440	Y	Sep 2020	US$ 1 999	amazon.com
12.		Panasonic S5 II	134 mm	102 mm	90 mm	740 g	370	Y	Jan 2023	US$ 1 999	amazon.com
13.		Sony A1	129 mm	97 mm	81 mm	737 g	530	Y	Jan 2021	US$ 6 499	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 A7 III	127 mm	96 mm	74 mm	650 g	610	Y	Feb 2018	US$ 1 999	amazon.com
16.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	US$ 4 499	ebay.com
17.		Sony A9 II	129 mm	96 mm	76 mm	678 g	690	Y	Oct 2019	US$ 4 499	amazon.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 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 G9 II was launched at a markedly lower price (by 68 percent) than the A9 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

The size of the sensor inside a digital camera is one of the key determinants 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. 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 A9 III a full frame sensor. The sensor area in the A9 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 A9 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 A9 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 A9 III). 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 G9 II has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

Unlike the A9 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 A9 III are ISO 250 to ISO 25600, with the possibility to increase the ISO range to 125-51200.

In terms of underlying technology, the G9 II is build around a CMOS sensor, while the A9 III uses a Stacked 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 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
1.		Panasonic G9 II	Four Thirds	25.0	5776	4336	5.7K/60p	23.4	13.5	1710	78
2.		Sony A9 III	Full Frame	24.0	6000	4000	4K/120p	25.4	14.7	3243	96
3.		Nikon Zf	Full Frame	24.3	6048	4024	4K/60p	25.4	14.7	3243	96
4.		Olympus E-M1 II	Four Thirds	20.2	5184	3888	4K/30p	23.7	12.8	1312	80
5.		Olympus E-M1 III	Four Thirds	20.2	5184	3888	4K/30p	23.3	13.1	1356	76
6.		OM System OM-1	Four Thirds	20.2	5184	3888	4K/60p	23.4	13.4	1553	77
7.		Panasonic G9	Four Thirds	20.2	5184	3888	4K/60p	23.1	12.8	1138	74
8.		Panasonic GH5	Four Thirds	20.2	5184	3888	4K/60p	23.9	13.0	807	77
9.		Panasonic GH5 II	Four Thirds	20.2	5184	3888	4K/60p	23.7	13.1	1136	79
10.		Panasonic GH6	Four Thirds	25.0	5776	4336	5.7K/60p	23.4	13.4	1555	77
11.		Panasonic S5	Full Frame	24.0	6000	4000	4K/60p	25.1	14.5	2697	94
12.		Panasonic S5 II	Full Frame	24.0	6000	4000	6K/30p	25.4	14.6	3158	96
13.		Sony A1	Full Frame	49.8	8640	5760	8k/30p	25.9	14.5	3163	98
14.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
15.		Sony A7 III	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3730	96
16.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
17.		Sony A9 II	Full Frame	24.0	6000	4000	4K/30p	25.0	14.0	3434	93
Note: DXO values in italics represent estimates based on sensor size and age.

Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the G9 II provides a higher video resolution than the A9 III. It can shoot video footage at 5.7K/60p, while the Sony is limited to 4K/120p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. The two cameras under review are similar with respect to both having an electronic viewfinder. However, the one in the A9 III offers a substantially higher resolution than the one in the G9 II (9440k vs 3680k dots). The table below summarizes some of the other core capabilities of the Panasonic G9 II and Sony A9 III in connection with corresponding information for a sample of similar 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 A9 III	9440	n	3.2 / 2100	full-flex	Y	1/80000s	120.0/s	n	Y
3.		Nikon Zf	3690	n	3.2 / 2100	swivel	Y	1/8000s	14.0/s	n	Y
4.		Olympus E-M1 II	2360	n	3.0 / 1037	swivel	Y	1/8000s	18.0/s	n	Y
5.		Olympus E-M1 III	2360	n	3.0 / 1037	swivel	Y	1/8000s	18.0/s	n	Y
6.		OM System OM-1	5760	n	3.0 / 1640	swivel	Y	1/8000s	10.0/s	n	Y
7.		Panasonic G9	3680	Y	3.0 / 1040	swivel	Y	1/8000s	20.0/s	n	Y
8.		Panasonic GH5	3680	n	3.2 / 1620	swivel	Y	1/8000s	12.0/s	n	Y
9.		Panasonic GH5 II	3680	n	3.0 / 1840	swivel	Y	1/8000s	12.0/s	n	Y
10.		Panasonic GH6	3680	n	3.0 / 1840	full-flex	Y	1/8000s	14.0/s	n	Y
11.		Panasonic S5	2360	n	3.0 / 1840	swivel	Y	1/8000s	7.0/s	n	Y
12.		Panasonic S5 II	3680	n	3.0 / 1840	swivel	Y	1/8000s	9.0/s	n	Y
13.		Sony A1	9437	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
14.		Sony A7 II	2400	n	3.0 / 1230	tilting	n	1/8000s	5.0/s	n	Y
15.		Sony A7 III	2359	n	3.0 / 922	tilting	Y	1/8000s	10.0/s	n	Y
16.		Sony A9	3686	n	3.0 / 1440	tilting	Y	1/8000s	20.0/s	n	Y
17.		Sony A9 II	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 A9 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 A9 III uses CFexpress (type A) or SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. Both cameras support UHS-II cards, which provide for Ultra High Speed data transfer of up to 312 MB/s.

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 A9 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 A9 III	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
3.		Nikon Zf	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
4.		Olympus E-M1 II	Y	stereo / mono	Y	Y	micro	3.0	Y	-	-
5.		Olympus E-M1 III	Y	stereo / mono	Y	Y	micro	3.1	Y	-	Y
6.		OM System OM-1	Y	stereo / mono	Y	Y	micro	3.0	Y	-	Y
7.		Panasonic G9	Y	stereo / mono	Y	Y	full	3.0	Y	-	Y
8.		Panasonic GH5	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
9.		Panasonic GH5 II	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
10.		Panasonic GH6	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
11.		Panasonic S5	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
12.		Panasonic S5 II	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
13.		Sony A1	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 A7 III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
16.		Sony A9	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
17.		Sony A9 II	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y

Studio photographers will appreciate that the Sony A9 III (unlike the G9 II) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the G9 II and the A9 III are recent models that are part of the current product line-up. The G9 II replaced the earlier Panasonic G9, while the A9 III followed on from the Sony A9 II. Further information on the features and operation of the G9 II and A9 III can be found, respectively, in the Panasonic G9 II Manual (free pdf) or the online Sony A9 III Manual.

Review summary

So how do things add up? Is the Panasonic G9 II better than the Sony A9 III or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Reasons to prefer 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/120p).
• More affordable: Was introduced into a lower priced category (68 percent cheaper at launch).

Advantages of the Sony Alpha A9 III:

• 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.
• More detailed viewfinder: Has higher resolution electronic viewfinder (9440k vs 3680k dots).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.9x vs 0.8x).
• Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (2100k vs 1840k dots).
• Faster shutter: Has higher mechanical shutter speed (1/80000s vs 1/8000s) to freeze action.
• Faster burst: Shoots at higher frequency (120 vs 10 flaps/sec) to capture the decisive moment.
• Longer lasting: Gets more shots (530 versus 390) out of a single battery charge.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.

If the count of individual advantages (bullet points above) is taken as a guide, the A9 III is the clear winner of the contest (13 : 4 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 G9 II and the Sony A9 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 A9 III 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.

Expert reviews

This is why expert reviews are important. The adjacent summary-table relays the overall verdicts of several of the most popular camera 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 A9 III	4.5/5	..	..	..	..	..	Nov 2023	US$ 5 999	amazon.com
3.		Nikon Zf	4.5/5	..	4.5/5	90/100	4.5/5	5/5	Sep 2023	US$ 1 999	amazon.com
4.		Olympus E-M1 II	5/5	+ +	5/5	85/100	4.5/5	4.5/5	Sep 2016	US$ 1 999	ebay.com
5.		Olympus E-M1 III	5/5	..	5/5	83/100	4.5/5	4/5	Feb 2020	US$ 1 799	ebay.com
6.		OM System OM-1	5/5	..	..	87/100	5/5	4.5/5	Feb 2022	US$ 2 199	ebay.com
7.		Panasonic G9	..	+ +	5/5	85/100	5/5	5/5	Nov 2017	US$ 1 699	ebay.com
8.		Panasonic GH5	4.5/5	+ +	..	85/100	4.5/5	5/5	Jan 2017	US$ 1 999	ebay.com
9.		Panasonic GH5 II	4.5/5	..	4.5/5	85/100	4.5/5	5/5	May 2021	US$ 1 699	amazon.com
10.		Panasonic GH6	5/5	+ +	5/5	87/100	5/5	5/5	Feb 2022	US$ 2 199	amazon.com
11.		Panasonic S5	4.5/5	+ +	4.5/5	88/100	4.5/5	4.5/5	Sep 2020	US$ 1 999	amazon.com
12.		Panasonic S5 II	4.5/5	+ +	5/5	90/100	4.5/5	5/5	Jan 2023	US$ 1 999	amazon.com
13.		Sony A1	5/5	o	4.5/5	93/100	4.5/5	5/5	Jan 2021	US$ 6 499	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 A7 III	..	+ +	4.5/5	89/100	5/5	5/5	Feb 2018	US$ 1 999	amazon.com
16.		Sony A9	5/5	+ +	4.8/5	89/100	5/5	5/5	Apr 2017	US$ 4 499	ebay.com
17.		Sony A9 II	..	..	5/5	90/100	5/5	5/5	Oct 2019	US$ 4 499	amazon.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, 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 rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

Check G9 II price at
amazon.com
Check A9 III price at
amazon.com

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.

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Check G9 II price at
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