Panasonic GH3 vs GM1

The Panasonic Lumix DMC-GH3 and the Panasonic Lumix DMC-GM1 are two digital cameras that were officially introduced, respectively, in September 2012 and October 2013. Both the GH3 and the GM1 are mirrorless interchangeable lens cameras that are equipped with a Four Thirds sensor. The GH3 has a resolution of 15.9 megapixels, whereas the GM1 provides 15.8 MP.

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

Headline Specifications

Panasonic GH3		Panasonic GM1
Mirrorless system camera		Mirrorless system camera
Micro Four Thirds lenses		Micro Four Thirds lenses
15.9 MP – Four Thirds sensor		15.8 MP – Four Thirds sensor
1080/60p Video		1080/60i Video
ISO 200-12,800 (125 - 25,600)		ISO 200-25,600
Electronic viewfinder (1746k dots)		No viewfinder, LCD framing
3.0" LCD – 614k dots		3.0" LCD – 1036k dots
Swivel touchscreen		Fixed touchscreen
6 shutter flaps per second		5 shutter flaps per second
Weathersealed body		not weather sealed
540 shots per battery charge		230 shots per battery charge
133 x 93 x 82 mm, 550 g		99 x 55 x 30 mm, 204 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Panasonic Lumix DMC-GH3 and the Panasonic Lumix DMC-GM1? 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 GH3 and the Panasonic GM1 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 GM1 can be obtained in three different colors (black, silver, red), while the GH3 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 GM1 is considerably smaller (56 percent) than the Panasonic GH3. Moreover, the GM1 is substantially lighter (63 percent) than the GH3. It is worth mentioning in this context that the GH3 is splash and dust resistant, 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. 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 GH3 gets 540 shots out of its DMW-BLF19 battery, while the GM1 can take 230 images on a single charge of its DMW-BLH7 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, 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 (USD)	Street Price
1.		Panasonic GH3	133 mm	93 mm	82 mm	550 g	540	Y	Sep 2012	1,299	ebay.com
2.		Panasonic GM1	99 mm	55 mm	30 mm	204 g	230	n	Oct 2013	749	ebay.com
3.		Olympus E-M5 II	124 mm	85 mm	45 mm	469 g	310	Y	Feb 2015	1,099	ebay.com
4.		Olympus E-M1	130 mm	94 mm	63 mm	497 g	350	Y	Sep 2013	1,399	ebay.com
5.		Olympus E-M5	122 mm	89 mm	43 mm	425 g	360	Y	Feb 2012	1,299	ebay.com
6.		Panasonic G85	128 mm	89 mm	74 mm	505 g	330	Y	Sep 2016	899	ebay.com
7.		Panasonic GX8	133 mm	78 mm	63 mm	487 g	330	Y	Jul 2015	1,199	ebay.com
8.		Panasonic GH4	133 mm	93 mm	84 mm	560 g	500	Y	Feb 2014	1,499	ebay.com
9.		Panasonic GM5	99 mm	60 mm	36 mm	211 g	220	n	Sep 2014	749	ebay.com
10.		Panasonic G6	122 mm	85 mm	71 mm	390 g	340	n	Apr 2013	599	ebay.com
11.		Panasonic GX7	123 mm	71 mm	55 mm	402 g	350	n	Aug 2013	999	ebay.com
12.		Panasonic G5	120 mm	83 mm	71 mm	396 g	320	n	Jul 2012	599	ebay.com
13.		Panasonic GX1	116 mm	68 mm	39 mm	318 g	320	n	Nov 2011	699	ebay.com
14.		Panasonic GH2	124 mm	90 mm	76 mm	442 g	330	n	Sep 2010	899	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 naturally be influenced heavily by the price. 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 GM1 was launched at a markedly lower price (by 42 percent) than the GH3, 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.

Sensor comparison

The imaging sensor is at the core of digital cameras and its size is one of the main determining factors 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 tend to be associated with larger, more expensive camera bodies 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 GH3 offers a slightly higher resolution of 15.9 megapixels, compared with 15.8 MP of the GM1. This megapixels advantage translates into a 0.3 percent gain in linear resolution. On the other hand, these sensor specs imply that the GH3 has a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.76μm versus 3.77μm for the GM1). Moreover, it should be noted that the GM1 is a somewhat more recent model (by 1 year) than the GH3, and its sensor might have benefitted from technological advances during this time that further enhance the light gathering capacity of individual pixels.

The Panasonic Lumix DMC-GH3 has a native sensitivity range from ISO 200 to ISO 12800, which can be extended to ISO 125-25600. The corresponding ISO settings for the Panasonic Lumix DMC-GM1 are ISO 200 to ISO 25600, with the possibility to increase the ISO range to 125-25600.

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 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 review, the GH3 has a notably higher overall DXO score than the GM1 (overall score 5 points higher), which gives it an advantage in terms of imaging quality. This advantage is based on 0.4 bits higher color depth, 0.7 EV in additional dynamic range, and 0.3 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
1.		Panasonic GH3	Four Thirds	15.9	4608	3456	1080/60p	22.7	12.4	812	71
2.		Panasonic GM1	Four Thirds	15.8	4592	3448	1080/60i	22.3	11.7	660	66
3.		Olympus E-M5 II	Four Thirds	15.9	4608	3456	1080/60p	23.0	12.5	842	73
4.		Olympus E-M1	Four Thirds	15.9	4608	3456	1080/30p	23.0	12.7	757	73
5.		Olympus E-M5	Four Thirds	15.9	4608	3456	1080/60i	22.8	12.3	826	71
6.		Panasonic G85	Four Thirds	15.8	4592	3448	4K/30p	22.8	12.5	656	71
7.		Panasonic GX8	Four Thirds	20.2	5184	3888	4K/30p	23.5	12.6	806	75
8.		Panasonic GH4	Four Thirds	15.9	4608	3456	4K/30p	23.2	12.8	791	74
9.		Panasonic GM5	Four Thirds	15.8	4592	3448	1080/60p	22.1	11.7	721	66
10.		Panasonic G6	Four Thirds	15.9	4608	3456	1080/60p	21.3	11.5	639	61
11.		Panasonic GX7	Four Thirds	15.8	4592	3448	1080/60p	22.6	12.2	718	70
12.		Panasonic G5	Four Thirds	15.9	4608	3456	1080/60p	21.4	11.6	618	61
13.		Panasonic GX1	Four Thirds	15.8	4592	3448	1080/60p	20.8	10.6	703	55
14.		Panasonic GH2	Four Thirds	15.9	4608	3456	1080/60i	21.2	11.3	655	60

Many modern cameras are not only capable of taking still images, but also of capturing video footage. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the GH3 provides a higher frame rate than the GM1. It can shoot video footage at 1080/60p, while the GM1 is limited to 1080/60i.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. For example, the GH3 has an electronic viewfinder (1746k 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 GH3, the Panasonic GM1, 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 GH3	1746	n	3.0 / 614	swivel	Y	1/4000s	6.0/s	Y	n
2.		Panasonic GM1	none	n	3.0 / 1036	fixed	Y	1/500s	5.0/s	Y	n
3.		Olympus E-M5 II	2360	n	3.0 / 1037	swivel	Y	1/8000s	10.0/s	n	Y
4.		Olympus E-M1	2360	n	3.0 / 1037	tilting	Y	1/8000s	10.0/s	n	Y
5.		Olympus E-M5	1440	n	3.0 / 610	tilting	Y	1/4000s	9.0/s	n	Y
6.		Panasonic G85	2360	n	3.0 / 1040	swivel	Y	1/4000s	9.0/s	Y	Y
7.		Panasonic GX8	2360	n	3.0 / 1040	swivel	Y	1/8000s	10.0/s	n	Y
8.		Panasonic GH4	2359	n	3.0 / 1036	swivel	Y	1/8000s	12.0/s	Y	n
9.		Panasonic GM5	1166	n	3.0 / 921	fixed	Y	1/500s	5.8/s	n	n
10.		Panasonic G6	1440	n	3.0 / 1036	swivel	Y	1/4000s	7.0/s	Y	n
11.		Panasonic GX7	2760	n	3.0 / 1040	tilting	Y	1/8000s	5.0/s	Y	Y
12.		Panasonic G5	1440	n	3.0 / 920	swivel	Y	1/4000s	6.0/s	Y	n
13.		Panasonic GX1	optional	n	3.0 / 460	fixed	Y	1/4000s	4.2/s	Y	n
14.		Panasonic GH2	1534	n	3.0 / 460	swivel	n	1/4000s	3.0/s	Y	n
Notes: *) 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 GH3 and the Panasonic GM1 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 GH3 and the GM1 write their files to SDXC cards. Both cameras can use UHS-I cards, which provide for Ultra High Speed data transfer of up to 104 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 DMC-GH3 and Panasonic Lumix DMC-GM1 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 GH3	Y	stereo / mono	Y	Y	mini	2.0	Y	-	-
2.		Panasonic GM1	-	stereo / mono	-	-	micro	2.0	Y	-	-
3.		Olympus E-M5 II	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
4.		Olympus E-M1	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
5.		Olympus E-M5	Y	stereo / mono	-	-	mini	2.0	-	-	-
6.		Panasonic G85	Y	stereo / mono	Y	-	micro	2.0	Y	-	-
7.		Panasonic GX8	Y	stereo / mono	Y	-	micro	2.0	Y	Y	-
8.		Panasonic GH4	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
9.		Panasonic GM5	Y	stereo / mono	-	-	micro	2.0	Y	-	-
10.		Panasonic G6	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
11.		Panasonic GX7	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
12.		Panasonic G5	Y	stereo / mono	-	-	mini	2.0	-	-	-
13.		Panasonic GX1	Y	stereo / mono	-	-	mini	2.0	-	-	-
14.		Panasonic GH2	Y	stereo / mono	Y	-	mini	2.0	-	-	-

It is notable that the GH3 has a hotshoe, while the GM1 does not. This socket makes it possible to easily attach optional accessories, such as an external flash gun.

Studio photographers will appreciate that the Panasonic GH3 (unlike the GM1) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the GH3 and the GM1 have been discontinued, but can regularly be found used on ebay. The GH3 was replaced by the Panasonic GH4, while the GM1 was followed by the Panasonic GM5. Further information on the features and operation of the GH3 and GM1 can be found, respectively, in the Panasonic GH3 Manual (free pdf) or the online Panasonic GM1 Manual.

Review summary

So what is the bottom line? Is there a clear favorite between the Panasonic GH3 and the Panasonic GM1? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.

Arguments in favor of the Panasonic Lumix DMC-GH3:

• Better image quality: Scores markedly higher (5 points) in the DXO overall assessment.
• More dynamic range: Captures a larger spectrum of light and dark details (0.7 EV of extra DR).
• Better video: Provides higher movie framerates (1080/60p versus 1080/60i).
• 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 composition and settings control.
• 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 (1/4000s vs 1/500s) to freeze action.
• Faster burst: Shoots at higher frequency (6 vs 5 flaps/sec) to capture the decisive moment.
• Longer lasting: Can take more shots (540 versus 230) on a single battery charge.
• Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• More heavily discounted: Has been on the market for longer (launched in September 2012).

Reasons to prefer the Panasonic Lumix DMC-GM1:

• More detailed LCD: Has a higher resolution rear screen (1036k vs 614k dots).
• More compact: Is smaller (99x55mm vs 133x93mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 346g or 63 percent) and is thus easier to take along.
• More affordable: Was introduced into a lower priced category (42 percent cheaper at launch).
• More modern: Was introduced somewhat (1 year) more recently.

If the number of relative strengths (bullet points above) is taken as a guide, the GH3 is the clear winner of the match-up (15 : 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 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 GH3 and the Panasonic GM1 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 the spec-sheets of cameras can offer a general idea of their imaging potential, it remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the GH3 or the GM1. 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.		Panasonic GH3	5/5	+ +	..	79/100	4.5/5	4.5/5	Sep 2012	1,299	ebay.com
2.		Panasonic GM1	3/5	+	..	78/100	5/5	4.5/5	Oct 2013	749	ebay.com
3.		Olympus E-M5 II	5/5	+ +	4.5/5	81/100	5/5	5/5	Feb 2015	1,099	ebay.com
4.		Olympus E-M1	5/5	+ +	..	84/100	4.5/5	4.5/5	Sep 2013	1,399	ebay.com
5.		Olympus E-M5	4/5	+ +	..	80/100	4.5/5	5/5	Feb 2012	1,299	ebay.com
6.		Panasonic G85	..	+ +	..	84/100	5/5	4.5/5	Sep 2016	899	ebay.com
7.		Panasonic GX8	5/5	+	..	82/100	4.5/5	4.5/5	Jul 2015	1,199	ebay.com
8.		Panasonic GH4	5/5	+ +	..	85/100	5/5	5/5	Feb 2014	1,499	ebay.com
9.		Panasonic GM5	3.5/5	+	..	77/100	5/5	4.5/5	Sep 2014	749	ebay.com
10.		Panasonic G6	4/5	+ +	..	..	5/5	4.5/5	Apr 2013	599	ebay.com
11.		Panasonic GX7	4/5	+	..	79/100	5/5	5/5	Aug 2013	999	ebay.com
12.		Panasonic G5	3/5	+ +	..	..	4.5/5	4.5/5	Jul 2012	599	ebay.com
13.		Panasonic GX1	3/5	+	..	77/100	4.5/5	4.5/5	Nov 2011	699	ebay.com
14.		Panasonic GH2	5/5	+ +	..	79/100	4.5/5	5/5	Sep 2010	899	ebay.com
Notes: (+ +) 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. Hence, a score should always be seen in the context of the camera's market launch date and its price, 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.

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Other camera comparisons

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