Olympus E-M1 III vs Panasonic GX9

The Olympus OM-D E-M1 Mark III and the Panasonic Lumix DC-GX9 are two enthusiast cameras that were revealed to the public, respectively, in February 2020 and February 2018. Both the E-M1 III and the GX9 are mirrorless interchangeable lens cameras that are equipped with a Four Thirds sensor. Both cameras offer a resolution of 20.2 megapixels.

Below is an overview of the main specs of the two cameras as a starting point for the comparison.

Headline Specifications

Olympus E-M1 III		Panasonic GX9
Mirrorless system camera		Mirrorless system camera
Micro Four Thirds lenses		Micro Four Thirds lenses
20.2 MP – Four Thirds sensor		20.2 MP – Four Thirds sensor
4K/30p Video		4K/30p Video
ISO 200-25,600		ISO 200-25,600
Electronic viewfinder (2360k dots)		Electronic viewfinder (2760k dots)
3.0" LCD – 1037k dots		3.0" LCD – 1240k dots
Swivel touchscreen		Tilting touchscreen
18 shutter flaps per second		9 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		not weather sealed
420 shots per battery charge		260 shots per battery charge
134 x 91 x 69 mm, 580 g		124 x 72 x 47 mm, 407 g

Check E-M1 III offers at
ebay.com
Check GX9 offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus OM-D E-M1 Mark III and the Panasonic Lumix DC-GX9? 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 physical size and weight of the Olympus E-M1 III and the Panasonic GX9 are illustrated 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 width, height and depth dimensions are rounded to the nearest millimeter.

The GX9 can be obtained in two different colors (black, silver), while the E-M1 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 Panasonic GX9 is notably smaller (27 percent) than the Olympus E-M1 III. Moreover, the GX9 is markedly lighter (30 percent) than the E-M1 III. It is worth mentioning in this context that the E-M1 III is splash and dust resistant, 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. In this particular case, both cameras feature the same lens mount, so that they can use the same lenses. You can compare the optics available in the Micro Four Thirds Lens Catalog. 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 E-M1 III gets 420 shots out of its Olympus BLH-1 battery, while the GX9 can take 260 images on a single charge of its Panasonic DMW-BLG10 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 (USD)	Street Price
1.		Olympus E-M1 III	134 mm	91 mm	69 mm	580 g	420	Y	Feb 2020	1,799	ebay.com
2.		Panasonic GX9	124 mm	72 mm	47 mm	407 g	260	n	Feb 2018	849	ebay.com
3.		Olympus E-M5 III	125 mm	85 mm	50 mm	414 g	310	Y	Oct 2019	1,199	ebay.com
4.		Olympus E-M1X	144 mm	147 mm	75 mm	997 g	870	Y	Jan 2019	2,999	ebay.com
5.		Olympus E-M1 II	134 mm	91 mm	67 mm	574 g	440	Y	Sep 2016	1,999	ebay.com
6.		Olympus E-M1	130 mm	94 mm	63 mm	497 g	350	Y	Sep 2013	1,399	ebay.com
7.		OM System OM-1	135 mm	92 mm	73 mm	599 g	520	Y	Feb 2022	2,199	ebay.com
8.		Panasonic GH5 II	139 mm	98 mm	87 mm	727 g	400	Y	May 2021	1,699	amazon.com
9.		Panasonic G95	130 mm	94 mm	77 mm	536 g	290	Y	Apr 2019	999	ebay.com
10.		Panasonic LX100 II	115 mm	66 mm	65 mm	392 g	300	n	Aug 2018	999	ebay.com
11.		Panasonic ZS200	111 mm	65 mm	45 mm	340 g	370	n	Feb 2018	799	amazon.com
12.		Panasonic G9	137 mm	97 mm	92 mm	658 g	400	Y	Nov 2017	1,699	ebay.com
13.		Panasonic GH5	139 mm	98 mm	87 mm	725 g	410	Y	Jan 2017	1,999	ebay.com
14.		Panasonic GX85	122 mm	71 mm	44 mm	426 g	290	n	Apr 2016	799	amazon.com
15.		Panasonic GX8	133 mm	78 mm	63 mm	487 g	330	Y	Jul 2015	1,199	ebay.com
16.		Panasonic GX7	123 mm	71 mm	55 mm	402 g	350	n	Aug 2013	999	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 GX9 was launched at a markedly lower price (by 53 percent) than the E-M1 III, which puts it into a different market segment. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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 sensor inside a digital camera is one of the key determinants of image quality. A large sensor will tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixel-units in a sensor of the same technological generation. Moreover, a large sensor camera will give the photographer more control over depth-of-field in the image and, thus, the ability to better 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.

Both cameras under consideration feature a Four Thirds sensor and have a format factor (sometimes also referred to as "crop factor") of 2.0. Within the spectrum of camera sensors, this places the review cameras among the medium-sized sensor cameras that aim to strike a balance between image quality and portability. Both cameras feature a native aspect ratio (sensor width to sensor height) of 4:3.

The two cameras under review do not only share the same sensor size, but also offer an identical resolution of 20.2 megapixels. This similarity in sensor specs implies that both the E-M1 III and the GX9 have the same pixel density, as well as the same pixel size. It should, however, be noted that the E-M1 III is a somewhat more recent model (by 1 year and 11 months) than the GX9, and its sensor might have benefitted from technological advances during this time. Coming back to sensor resolution, it should be mentioned that neither of the two cameras has an anti-alias filter installed, so they are able to capture all the detail the sensor resolves.

The E-M1 III has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

Unlike the GX9, the E-M1 III has the capacity to capture high quality composite images (80MP) 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 Olympus OM-D E-M1 Mark III has a native sensitivity range from ISO 200 to ISO 25600, which can be extended to ISO 64-25600. The corresponding ISO settings for the Panasonic Lumix DC-GX9 are ISO 200 to ISO 25600, with the possibility to increase the ISO range to 100-25600.

Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) sensors. 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.		Olympus E-M1 III	Four Thirds	20.2	5184	3888	4K/30p	23.3	13.1	1356	76
2.		Panasonic GX9	Four Thirds	20.2	5184	3888	4K/30p	23.1	12.8	1163	74
3.		Olympus E-M5 III	Four Thirds	20.2	5184	3888	4K/30p	23.3	13.1	1324	76
4.		Olympus E-M1X	Four Thirds	20.2	5184	3888	4K/30p	23.2	13.0	1254	75
5.		Olympus E-M1 II	Four Thirds	20.2	5184	3888	4K/30p	23.7	12.8	1312	80
6.		Olympus E-M1	Four Thirds	15.9	4608	3456	1080/30p	23.0	12.7	757	73
7.		OM System OM-1	Four Thirds	20.2	5184	3888	4K/60p	23.4	13.4	1553	77
8.		Panasonic GH5 II	Four Thirds	20.2	5184	3888	4K/60p	23.7	13.1	1136	79
9.		Panasonic G95	Four Thirds	20.2	5184	3888	4K/30p	23.2	13.0	1273	75
10.		Panasonic LX100 II	Four Thirds	16.8	4736	3552	4K/30p	22.8	12.7	979	72
11.		Panasonic ZS200	1-inch	20.0	5472	3648	4K/30p	22.0	12.2	449	64
12.		Panasonic G9	Four Thirds	20.2	5184	3888	4K/60p	23.1	12.8	1138	74
13.		Panasonic GH5	Four Thirds	20.2	5184	3888	4K/60p	23.9	13.0	807	77
14.		Panasonic GX85	Four Thirds	15.8	4592	3448	4K/30p	22.9	12.6	662	71
15.		Panasonic GX8	Four Thirds	20.2	5184	3888	4K/30p	23.5	12.6	806	75
16.		Panasonic GX7	Four Thirds	15.8	4592	3448	1080/60p	22.6	12.2	718	70
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 have a sensor with sufficiently fast read-out times for moving pictures, and both provide the same movie specifications (4K/30p).

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The two cameras under review 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 E-M1 III (2760k vs 2360k dots). The adjacent table lists some of the other core features of the Olympus E-M1 III and Panasonic GX9 along with similar information for a selection of comparators.

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.		Olympus E-M1 III	2360	n	3.0 / 1037	swivel	Y	1/8000s	18.0/s	n	Y
2.		Panasonic GX9	2760	n	3.0 / 1240	tilting	Y	1/4000s	9.0/s	Y	Y
3.		Olympus E-M5 III	2360	n	3.0 / 1040	swivel	Y	1/8000s	10.0/s	n	Y
4.		Olympus E-M1X	2360	n	3.0 / 1037	swivel	Y	1/8000s	18.0/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	2360	n	3.0 / 1037	tilting	Y	1/8000s	10.0/s	n	Y
7.		OM System OM-1	5760	n	3.0 / 1640	swivel	Y	1/8000s	10.0/s	n	Y
8.		Panasonic GH5 II	3680	n	3.0 / 1840	swivel	Y	1/8000s	12.0/s	n	Y
9.		Panasonic G95	2360	n	3.0 / 1240	swivel	Y	1/4000s	9.0/s	Y	Y
10.		Panasonic LX100 II	2764	n	3.0 / 1240	fixed	Y	1/4000s	11.0/s	n	Y
11.		Panasonic ZS200	2330	n	3.0 / 1240	fixed	Y	1/2000s	10.0/s	Y	Y
12.		Panasonic G9	3680	Y	3.0 / 1040	swivel	Y	1/8000s	20.0/s	n	Y
13.		Panasonic GH5	3680	n	3.2 / 1620	swivel	Y	1/8000s	12.0/s	n	Y
14.		Panasonic GX85	2765	n	3.0 / 1040	tilting	Y	1/4000s	8.0/s	Y	Y
15.		Panasonic GX8	2360	n	3.0 / 1040	swivel	Y	1/8000s	10.0/s	n	Y
16.		Panasonic GX7	2760	n	3.0 / 1040	tilting	Y	1/8000s	5.0/s	Y	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One difference between the cameras concerns the presence of an on-board flash. The GX9 has one, while the E-M1 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 Olympus E-M1 III and the Panasonic GX9 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.

Concerning the storage of imaging data, both the E-M1 III and the GX9 write their files to SDXC cards. The E-M1 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 E-M1 III supports UHS-II cards (on its first slot), while the GX9 can use UHS-I cards.

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 Olympus OM-D E-M1 Mark III and Panasonic Lumix DC-GX9 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.		Olympus E-M1 III	Y	stereo / mono	Y	Y	micro	3.1	Y	-	Y
2.		Panasonic GX9	Y	stereo / mono	-	-	micro	2.0	Y	-	Y
3.		Olympus E-M5 III	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
4.		Olympus E-M1X	Y	stereo / mono	Y	Y	micro	3.0	Y	-	Y
5.		Olympus E-M1 II	Y	stereo / mono	Y	Y	micro	3.0	Y	-	-
6.		Olympus E-M1	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
7.		OM System OM-1	Y	stereo / mono	Y	Y	micro	3.0	Y	-	Y
8.		Panasonic GH5 II	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
9.		Panasonic G95	Y	stereo / mono	Y	Y	micro	2.0	Y	-	Y
10.		Panasonic LX100 II	Y	stereo / mono	-	-	micro	2.0	Y	-	Y
11.		Panasonic ZS200	-	stereo / mono	-	-	micro	2.0	Y	-	Y
12.		Panasonic G9	Y	stereo / mono	Y	Y	full	3.0	Y	-	Y
13.		Panasonic GH5	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
14.		Panasonic GX85	Y	stereo / mono	-	-	micro	2.0	Y	-	-
15.		Panasonic GX8	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-
16.		Panasonic GX7	Y	stereo / mono	-	-	mini	2.0	Y	Y	-

It is notable that the E-M1 III has a microphone port, which is missing on the GX9. Such an external microphone input can help to substantially improve the quality of audio recordings when a good external microphone is used.

Studio photographers will appreciate that the Olympus E-M1 III (unlike the GX9) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the E-M1 III and the GX9 have been discontinued, but can regularly be found used on ebay. The E-M1 III was replaced by the OM System OM-1, while the GX9 does not have a direct successor. Further information on the features and operation of the E-M1 III and GX9 can be found, respectively, in the Olympus E-M1 III Manual (free pdf) or the online Panasonic GX9 Manual.

Review summary

So how do things add up? Is there a clear favorite between the Olympus E-M1 III and the Panasonic GX9? Which camera is better? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Olympus OM-D E-M1 Mark III:

• High quality composites: Can combine several shots after pixel-shifting its sensor.
• 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 (0.74x vs 0.70x).
• 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 shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (18 vs 9 flaps/sec) to capture the decisive moment.
• Longer lasting: Can take more shots (420 versus 260) on a single battery charge.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• Faster data transfer: Supports a more advanced USB protocol (3.1 vs 2.0).
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• 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).
• More modern: Is somewhat more recent (announced 1 year and 11 months after the GX9).

Advantages of the Panasonic Lumix DC-GX9:

• More detailed viewfinder: Has higher resolution electronic viewfinder (2760k vs 2360k dots).
• More detailed LCD: Has a higher resolution rear screen (1240k vs 1037k dots).
• More compact: Is smaller (124x72mm vs 134x91mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 173g or 30 percent) and is thus easier to take along.
• Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
• More affordable: Was introduced into a lower priced category (53 percent cheaper at launch).
• More heavily discounted: Has been on the market for longer (launched in February 2018).

If the count of individual advantages (bullet points above) is taken as a guide, the E-M1 III is the clear winner of the match-up (16 : 7 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. A professional wedding photographer will view the differences between cameras in a way that diverges from the perspective of a travel photog, and a person interested in cityscapes has distinct needs from a macro 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 Olympus E-M1 III and the Panasonic GX9 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 specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it remains incomplete and does no justice, for example, to the way the E-M1 III or the GX9 perform in practice. 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 hands-on reviews by experts are important. The following table reports the overall ratings of the cameras as published by some of the major 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 (USD)	Street Price
1.		Olympus E-M1 III	5/5	..	5/5	83/100	4.5/5	4/5	Feb 2020	1,799	ebay.com
2.		Panasonic GX9	4/5	+	4/5	84/100	4.5/5	4.5/5	Feb 2018	849	ebay.com
3.		Olympus E-M5 III	5/5	+	5/5	82/100	4.5/5	4.5/5	Oct 2019	1,199	ebay.com
4.		Olympus E-M1X	4.5/5	o	5/5	85/100	4.5/5	..	Jan 2019	2,999	ebay.com
5.		Olympus E-M1 II	5/5	+ +	5/5	85/100	4.5/5	4.5/5	Sep 2016	1,999	ebay.com
6.		Olympus E-M1	5/5	+ +	..	84/100	4.5/5	4.5/5	Sep 2013	1,399	ebay.com
7.		OM System OM-1	5/5	..	..	87/100	5/5	4.5/5	Feb 2022	2,199	ebay.com
8.		Panasonic GH5 II	4.5/5	..	4.5/5	85/100	4.5/5	5/5	May 2021	1,699	amazon.com
9.		Panasonic G95	4.5/5	+	4.5/5	83/100	4.5/5	4.5/5	Apr 2019	999	ebay.com
10.		Panasonic LX100 II	4.5/5	+	4.2/5	82/100	4.5/5	4.5/5	Aug 2018	999	ebay.com
11.		Panasonic ZS200	..	+ +	4.5/5	81/100	4.5/5	4.5/5	Feb 2018	799	amazon.com
12.		Panasonic G9	..	+ +	5/5	85/100	5/5	5/5	Nov 2017	1,699	ebay.com
13.		Panasonic GH5	4.5/5	+ +	..	85/100	4.5/5	5/5	Jan 2017	1,999	ebay.com
14.		Panasonic GX85	4.5/5	+ +	..	82/100	5/5	5/5	Apr 2016	799	amazon.com
15.		Panasonic GX8	5/5	+	..	82/100	4.5/5	4.5/5	Jul 2015	1,199	ebay.com
16.		Panasonic GX7	4/5	+	..	79/100	5/5	5/5	Aug 2013	999	ebay.com
Note: (+ +) 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. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, and comparisons of ratings among very different cameras or across long time periods have little meaning. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

Check E-M1 III offers at
ebay.com
Check GX9 offers at
ebay.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 use the search menu below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

~

Check E-M1 III offers at
ebay.com
Check GX9 offers at
ebay.com

Did you notice an error on this page? If so, please get in touch, so that we can correct the information.