OM System OM-3 vs Panasonic GH7

The OM System OM-3 and the Panasonic Lumix DC-GH7 are two enthusiast cameras that were revealed to the public, respectively, in February 2025 and June 2024. Both the OM-3 and the GH7 are mirrorless interchangeable lens cameras that are equipped with a Four Thirds sensor. The OM System has a resolution of 20.2 megapixels, whereas the Panasonic provides 25 MP.

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

Headline Specifications

OM System OM-3		Panasonic GH7
Mirrorless system camera		Mirrorless system camera
Micro Four Thirds lenses		Micro Four Thirds lenses
20.2 MP – Four Thirds sensor		25 MP – Four Thirds sensor
4K/60p Video		5.7K/60p Video
ISO 80-25,600 (80 - 102,400)		ISO 100-25,600
Electronic viewfinder (2360k dots)		Electronic viewfinder (3680k dots)
3.0" LCD – 1640k dots		3.0" LCD – 1840k dots
Swivel touchscreen		Fully flexible touchscreen
6 shutter flaps per second		14 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		Weathersealed body
590 shots per battery charge		380 shots per battery charge
139 x 89 x 46 mm, 496 g		138 x 100 x 100 mm, 805 g

Check OM-3 price at
amazon.com
Check GH7 price at
amazon.com

Going beyond this snapshot of core features and characteristics, what are the differences between the OM System OM-3 and the Panasonic Lumix DC-GH7? 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 OM System OM-3 and the Panasonic GH7 is provided 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 width, height and depth dimensions are rounded to the nearest millimeter.

The OM-3 can be obtained in two different colors (black, silver), while the GH7 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 GH7 is notably larger (12 percent) than the OM System OM-3. Moreover, the GH7 is substantially heavier (62 percent) than the OM-3. 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. 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 OM-3 gets 590 shots out of its OM System BLX-1 battery, while the GH7 can take 380 images on a single charge of its Panasonic DMW-BLK22 power pack. The battery packs of both cameras can be charged via USB, which can be very convenient when travelling.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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.		OM System OM-3	139 mm	89 mm	46 mm	496 g	590	Y	Feb 2025	US$ 1 999	amazon.com
2.		Panasonic GH7	138 mm	100 mm	100 mm	805 g	380	Y	Jun 2024	US$ 2 199	amazon.com
3.		Olympus E-M1 II	134 mm	91 mm	67 mm	574 g	440	Y	Sep 2016	US$ 1 999	ebay.com
4.		Olympus E-M1 III	134 mm	91 mm	69 mm	580 g	420	Y	Feb 2020	US$ 1 799	ebay.com
5.		Olympus E-M5 III	125 mm	85 mm	50 mm	414 g	310	Y	Oct 2019	US$ 1 199	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.		OM System OM-1 II	135 mm	92 mm	73 mm	599 g	500	Y	Jan 2024	US$ 2 399	amazon.com
8.		OM System OM-5	125 mm	85 mm	50 mm	414 g	310	Y	Oct 2022	US$ 1 199	amazon.com
9.		OM System OM-5 II	125 mm	85 mm	50 mm	414 g	310	Y	Jun 2025	US$ 1 199	amazon.com
10.		Panasonic G9	137 mm	97 mm	92 mm	658 g	400	Y	Nov 2017	US$ 1 699	ebay.com
11.		Panasonic G9 II	134 mm	102 mm	90 mm	658 g	390	Y	Sep 2023	US$ 1 899	amazon.com
12.		Panasonic G90	130 mm	94 mm	77 mm	536 g	290	Y	Apr 2019	US$ 999	ebay.com
13.		Panasonic GH5	139 mm	98 mm	87 mm	725 g	410	Y	Jan 2017	US$ 1 999	ebay.com
14.		Panasonic GH6	138 mm	100 mm	100 mm	823 g	360	Y	Feb 2022	US$ 2 199	amazon.com
15.		Panasonic S5	133 mm	98 mm	82 mm	714 g	440	Y	Sep 2020	US$ 1 999	amazon.com
16.		Panasonic S5 II	134 mm	102 mm	90 mm	740 g	370	Y	Jan 2023	US$ 1 999	amazon.com
17.		Sony A7C	124 mm	71 mm	60 mm	509 g	740	Y	Sep 2020	US$ 1 799	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

The price is, of course, an important factor in any camera decision. The manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The OM-3 was somewhat cheaper (by 9 percent) than the GH7 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. 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. Further, a large sensor camera will give the photographer additional creative options when using shallow depth-of-field to isolate a subject from its background. On the downside, larger sensors tend to be more expensive and 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.

While the two cameras under review share the same sensor size, the GH7 offers a higher resolution of 25 megapixels, compared with 20.2 MP of the OM-3. This megapixels advantage translates into a 11 percent gain in linear resolution. On the other hand, these sensor specs imply that the GH7 has a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.00μm versus 3.34μm for the OM-3). Moreover, it should be noted, that the OM-3 is a somewhat more recent model (by 8 months) than the GH7, and its sensor might have benefitted from technological advances during this time that further enhance the light gathering capacity of individual pixels. 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 resolution advantage of the Panasonic GH7 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the GH7 for good quality output (200 dots per inch) amounts to 28.9 x 21.7 inches or 73.4 x 55.1 cm, for very good quality (250 dpi) 23.1 x 17.3 inches or 58.7 x 44.1 cm, and for excellent quality (300 dpi) 19.3 x 14.5 inches or 48.9 x 36.7 cm. The corresponding values for the OM System OM-3 are 25.9 x 19.4 inches or 65.8 x 49.4 cm for good quality, 20.7 x 15.6 inches or 52.7 x 39.5 cm for very good quality, and 17.3 x 13 inches or 43.9 x 32.9 cm for excellent quality prints.

Both cameras have the capacity to capture high quality composite images by combining multiple shots after shifting the sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).

The OM System OM-3 has a native sensitivity range from ISO 80 to ISO 25600, which can be extended to ISO 80-102400. The corresponding ISO settings for the Panasonic Lumix DC-GH7 are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 50-25600.

In terms of underlying technology, the OM-3 is build around a Stacked BSI-CMOS sensor, while the GH7 uses a 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.

For many cameras, data on sensor performance has been reported by DXO Mark. 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"). 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.		OM System OM-3	Four Thirds	20.2	5184	3888	4K/60p	23.4	13.7	1852	78
2.		Panasonic GH7	Four Thirds	25.0	5776	4336	5.7K/60p	23.4	13.6	1784	78
3.		Olympus E-M1 II	Four Thirds	20.2	5184	3888	4K/30p	23.7	12.8	1312	80
4.		Olympus E-M1 III	Four Thirds	20.2	5184	3888	4K/30p	23.3	13.1	1356	76
5.		Olympus E-M5 III	Four Thirds	20.2	5184	3888	4K/30p	23.3	13.1	1324	76
6.		OM System OM-1	Four Thirds	20.2	5184	3888	4K/60p	23.4	13.4	1553	77
7.		OM System OM-1 II	Four Thirds	20.2	5184	3888	4K/60p	23.4	13.6	1749	78
8.		OM System OM-5	Four Thirds	20.2	5184	3888	4K/30p	23.4	13.4	1622	78
9.		OM System OM-5 II	Four Thirds	20.2	5184	3888	4K/30p	23.4	13.7	1889	78
10.		Panasonic G9	Four Thirds	20.2	5184	3888	4K/60p	23.1	12.8	1138	74
11.		Panasonic G9 II	Four Thirds	25.0	5776	4336	5.7K/60p	23.4	13.5	1710	78
12.		Panasonic G90	Four Thirds	20.2	5184	3888	4K/30p	23.2	13.0	1273	75
13.		Panasonic GH5	Four Thirds	20.2	5184	3888	4K/60p	23.9	13.0	807	77
14.		Panasonic GH6	Four Thirds	25.0	5776	4336	5.7K/60p	23.4	13.4	1555	77
15.		Panasonic S5	Full Frame	24.0	6000	4000	4K/60p	25.1	14.5	2697	94
16.		Panasonic S5 II	Full Frame	24.0	6000	4000	6K/30p	25.4	14.6	3158	96
17.		Sony A7C	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3407	95
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. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the GH7 provides a better video resolution than the OM-3. It can shoot movie footage at 5.7K/60p, while the OM System is limited to 4K/60p.

Feature comparison

Beyond 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 GH7 offers a substantially higher resolution than the one in the OM-3 (3680k vs 2360k dots). The following table reports on some other key feature differences and similarities of the OM System OM-3, the Panasonic GH7, 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.		OM System OM-3	2360	n	3.0 / 1640	swivel	Y	1/8000s	6.0/s	n	Y
2.		Panasonic GH7	3680	n	3.0 / 1840	full-flex	Y	1/8000s	14.0/s	n	Y
3.		Olympus E-M1 II	2360	n	3.0 / 1037	swivel	Y	1/8000s	18.0/s	n	Y
4.		Olympus E-M1 III	2360	n	3.0 / 1037	swivel	Y	1/8000s	18.0/s	n	Y
5.		Olympus E-M5 III	2360	n	3.0 / 1040	swivel	Y	1/8000s	10.0/s	n	Y
6.		OM System OM-1	5760	n	3.0 / 1640	swivel	Y	1/8000s	10.0/s	n	Y
7.		OM System OM-1 II	5760	n	3.0 / 1640	swivel	Y	1/8000s	10.0/s	n	Y
8.		OM System OM-5	2360	n	3.0 / 1040	swivel	Y	1/8000s	10.0/s	n	Y
9.		OM System OM-5 II	2360	n	3.0 / 1040	swivel	Y	1/8000s	10.0/s	n	Y
10.		Panasonic G9	3680	Y	3.0 / 1040	swivel	Y	1/8000s	20.0/s	n	Y
11.		Panasonic G9 II	3680	n	3.0 / 1840	swivel	Y	1/8000s	10.0/s	n	Y
12.		Panasonic G90	2360	n	3.0 / 1240	swivel	Y	1/4000s	9.0/s	Y	Y
13.		Panasonic GH5	3680	n	3.2 / 1620	swivel	Y	1/8000s	12.0/s	n	Y
14.		Panasonic GH6	3680	n	3.0 / 1840	full-flex	Y	1/8000s	14.0/s	n	Y
15.		Panasonic S5	2360	n	3.0 / 1840	swivel	Y	1/8000s	7.0/s	n	Y
16.		Panasonic S5 II	3680	n	3.0 / 1840	swivel	Y	1/8000s	9.0/s	n	Y
17.		Sony A7C	2360	n	3.0 / 922	swivel	Y	1/4000s	10.0/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 OM System OM-3 and the Panasonic GH7 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 OM-3 writes its imaging data to SDXC cards, while the GH7 uses CFexpress (type B) or SDXC cards. The GH7 features dual card slots, which can be very useful in case a memory card fails. In contrast, the OM-3 only has one slot. Moreover, both cameras support UHS-II cards (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 OM System OM-3 and Panasonic Lumix DC-GH7 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.		OM System OM-3	Y	stereo / mono	Y	Y	micro	3.0	Y	-	Y
2.		Panasonic GH7	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
3.		Olympus E-M1 II	Y	stereo / mono	Y	Y	micro	3.0	Y	-	-
4.		Olympus E-M1 III	Y	stereo / mono	Y	Y	micro	3.1	Y	-	Y
5.		Olympus E-M5 III	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
6.		OM System OM-1	Y	stereo / mono	Y	Y	micro	3.0	Y	-	Y
7.		OM System OM-1 II	Y	stereo / mono	Y	Y	micro	3.0	Y	-	Y
8.		OM System OM-5	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
9.		OM System OM-5 II	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
10.		Panasonic G9	Y	stereo / mono	Y	Y	full	3.0	Y	-	Y
11.		Panasonic G9 II	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
12.		Panasonic G90	Y	stereo / mono	Y	Y	micro	2.0	Y	-	Y
13.		Panasonic GH5	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
14.		Panasonic GH6	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
15.		Panasonic S5	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
16.		Panasonic S5 II	Y	stereo / mono	Y	Y	full	3.2	Y	-	Y
17.		Sony A7C	Y	stereo / mono	Y	Y	micro	3.2	Y	Y	Y

Studio photographers will appreciate that the Panasonic GH7 (unlike the OM-3) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the OM-3 and the GH7 are recent models that are part of the current product line-up. The GH7 replaced the earlier Panasonic GH6, while the OM-3 does not have a direct predecessor. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official OM System and Panasonic websites.

Review summary

So how do things add up? Is the OM System OM-3 better than the Panasonic GH7 or vice versa? The listing below highlights the relative strengths of the two models.

Reasons to prefer the OM System OM-3:

• Less heavy: Is lighter (by 309g or 38 percent) and hence easier to carry around.
• Longer lasting: Can take more shots (590 versus 380) on a single battery charge.
• More modern: Is somewhat more recent (announced 8 months after the GH7).

Arguments in favor of the Panasonic Lumix DC-GH7:

• More detail: Has more megapixels (25 vs 20.2MP), which boosts linear resolution by 11%.
• Better video: Provides higher definition movie capture (5.7K/60p vs 4K/60p).
• More detailed viewfinder: Has higher resolution electronic viewfinder (3680k vs 2360k dots).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.8x vs 0.69x).
• More detailed LCD: Has a higher resolution rear screen (1840k vs 1640k dots).
• Faster burst: Shoots at higher frequency (14 vs 6 flaps/sec) to capture the decisive moment.
• More solid recording: Has a full-sized HDMI port for a sturdy connection to an external recorder.
• 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.
• More heavily discounted: Has been on the market for longer (launched in June 2024).

If the count of relative strengths (bullet points above) is taken as a measure, the GH7 is the clear winner of the contest (10 : 3 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 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 OM System OM-3 and the Panasonic GH7 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 OM-3 or the GH7 perform in practice. 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 why hands-on reviews by experts are important. 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.		OM System OM-3	..	..	..	86/100	..	..	Feb 2025	US$ 1 999	amazon.com
2.		Panasonic GH7	..	..	..	..	..	..	Jun 2024	US$ 2 199	amazon.com
3.		Olympus E-M1 II	5/5	+ +	5/5	85/100	4.5/5	4.5/5	Sep 2016	US$ 1 999	ebay.com
4.		Olympus E-M1 III	5/5	..	5/5	83/100	4.5/5	4/5	Feb 2020	US$ 1 799	ebay.com
5.		Olympus E-M5 III	5/5	+	5/5	82/100	4.5/5	4.5/5	Oct 2019	US$ 1 199	ebay.com
6.		OM System OM-1	5/5	..	..	87/100	5/5	4.5/5	Feb 2022	US$ 2 199	ebay.com
7.		OM System OM-1 II	..	..	..	..	..	..	Jan 2024	US$ 2 399	amazon.com
8.		OM System OM-5	5/5	..	4.5/5	83/100	5/5	4.5/5	Oct 2022	US$ 1 199	amazon.com
9.		OM System OM-5 II	..	..	..	..	..	..	Jun 2025	US$ 1 199	amazon.com
10.		Panasonic G9	..	+ +	5/5	85/100	5/5	5/5	Nov 2017	US$ 1 699	ebay.com
11.		Panasonic G9 II	5/5	..	4.5/5	87/100	..	4.5/5	Sep 2023	US$ 1 899	amazon.com
12.		Panasonic G90	4.5/5	+	4.5/5	83/100	4.5/5	4.5/5	Apr 2019	US$ 999	ebay.com
13.		Panasonic GH5	4.5/5	+ +	..	85/100	4.5/5	5/5	Jan 2017	US$ 1 999	ebay.com
14.		Panasonic GH6	5/5	+ +	5/5	87/100	5/5	5/5	Feb 2022	US$ 2 199	amazon.com
15.		Panasonic S5	4.5/5	+ +	4.5/5	88/100	4.5/5	4.5/5	Sep 2020	US$ 1 999	amazon.com
16.		Panasonic S5 II	4.5/5	+ +	5/5	90/100	4.5/5	5/5	Jan 2023	US$ 1 999	amazon.com
17.		Sony A7C	3.5/5	..	3.5/5	86/100	4/5	4/5	Sep 2020	US$ 1 799	amazon.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 comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

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Other camera comparisons

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