Panasonic G3 vs GM1

The Panasonic Lumix DMC-G3 and the Panasonic Lumix DMC-GM1 are two digital cameras that were revealed to the public, respectively, in May 2011 and October 2013. Both the G3 and the GM1 are mirrorless interchangeable lens cameras that are equipped with a Four Thirds sensor. Both cameras offer a resolution of 15.8 megapixels.

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

Headline Specifications

Panasonic G3		Panasonic GM1
Mirrorless system camera		Mirrorless system camera
Micro Four Thirds lenses		Micro Four Thirds lenses
15.8 MP – Four Thirds sensor		15.8 MP – Four Thirds sensor
1080/60i Video		1080/60i Video
ISO 160-6,400		ISO 200-25,600
Electronic viewfinder (1440k dots)		No viewfinder, LCD framing
3.0" LCD – 460k dots		3.0" LCD – 1036k dots
Swivel touchscreen		Fixed touchscreen
4 shutter flaps per second		5 shutter flaps per second
270 shots per battery charge		230 shots per battery charge
115 x 84 x 47 mm, 336 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-G3 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

The side-by-side display below illustrates the physical size and weight of the Panasonic G3 and the Panasonic GM1. 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 G3 can be obtained in four different colors (black, brown, red, white), while the GM1 is available in three color-versions (black, silver, red).

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 (44 percent) than the Panasonic G3. Moreover, the GM1 is substantially lighter (39 percent) than the G3. In this context, it is worth noting that neither the G3 nor the GM1 are weather-sealed.

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 G3 gets 270 shots out of its Panasonic DMW-BLD10 battery, while the GM1 can take 230 images on a single charge of its Panasonic 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	Street Price
1.		Panasonic G3	115 mm	84 mm	47 mm	336 g	270	n	May 2011	US$ 599	ebay.com
2.		Panasonic GM1	99 mm	55 mm	30 mm	204 g	230	n	Oct 2013	US$ 749	ebay.com
3.		Panasonic G1	124 mm	84 mm	45 mm	360 g	410	n	Sep 2008	US$ 599	ebay.com
4.		Panasonic G2	124 mm	84 mm	74 mm	428 g	360	n	Mar 2010	US$ 599	ebay.com
5.		Panasonic G5	120 mm	83 mm	71 mm	396 g	320	n	Jul 2012	US$ 599	ebay.com
6.		Panasonic G6	122 mm	85 mm	71 mm	390 g	340	n	Apr 2013	US$ 599	ebay.com
7.		Panasonic G10	124 mm	84 mm	74 mm	388 g	380	n	Mar 2010	US$ 499	ebay.com
8.		Panasonic GF2	113 mm	68 mm	33 mm	310 g	300	n	Nov 2010	US$ 549	ebay.com
9.		Panasonic GF3	108 mm	67 mm	32 mm	264 g	300	n	Jun 2011	US$ 549	ebay.com
10.		Panasonic GF6	111 mm	65 mm	38 mm	323 g	340	n	Apr 2013	US$ 499	ebay.com
11.		Panasonic GH2	124 mm	90 mm	76 mm	442 g	330	n	Sep 2010	US$ 899	ebay.com
12.		Panasonic GM5	99 mm	60 mm	36 mm	211 g	220	n	Sep 2014	US$ 749	ebay.com
13.		Panasonic GX1	116 mm	68 mm	39 mm	318 g	320	n	Nov 2011	US$ 699	ebay.com
14.		Panasonic GX7	123 mm	71 mm	55 mm	402 g	350	n	Aug 2013	US$ 999	ebay.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
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The price is, of course, an important factor in any camera decision. The retail prices at the time of the camera’s release place the model in the market relative to other models in the producer’s line-up and the competition. The G3 was launched at a somewhat lower price (by 20 percent) than the GM1, which makes it more attractive for photographers on a tight budget. 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 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. 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 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 15.8 megapixels. This similarity in sensor specs implies that both the G3 and the GM1 have the same pixel density, as well as the same pixel size. It should, however, be noted that the GM1 is much more recent (by 2 years and 5 months) than the G3, and its sensor will have benefitted from technological advances during this time.

The Panasonic Lumix DMC-G3 has a native sensitivity range from ISO 160 to ISO 6400. 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.

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. This service assesses and scores the color depth ("DXO Portrait"), dynamic range ("DXO Landscape"), and low-light sensitivity ("DXO Sports") of camera sensors, and also publishes an overall camera score. Of the two cameras under consideration, the GM1 has a markedly higher DXO score than the G3 (overall score 10 points higher), which will translate into better image quality. The advantage is based on 1.3 bits higher color depth, 1.1 EV in additional dynamic range, and 0 stops of reduced low light sensitivity. 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 G3	Four Thirds	15.8	4592	3448	1080/60i	21.0	10.6	667	56
2.		Panasonic GM1	Four Thirds	15.8	4592	3448	1080/60i	22.3	11.7	660	66
3.		Panasonic G1	Four Thirds	12.0	4000	3000	none	21.1	10.3	463	53
4.		Panasonic G2	Four Thirds	12.0	4000	3000	720/30p	21.2	10.3	493	53
5.		Panasonic G5	Four Thirds	15.9	4608	3456	1080/60p	21.4	11.6	618	61
6.		Panasonic G6	Four Thirds	15.9	4608	3456	1080/60p	21.3	11.5	639	61
7.		Panasonic G10	Four Thirds	12.0	4000	3000	720/30p	21.2	10.1	411	52
8.		Panasonic GF2	Four Thirds	12.0	4000	3000	1080/60i	21.2	10.3	506	54
9.		Panasonic GF3	Four Thirds	12.0	4000	3000	1080/60i	20.6	10.1	459	50
10.		Panasonic GF6	Four Thirds	15.8	4592	3448	1080/60i	20.7	10.6	622	54
11.		Panasonic GH2	Four Thirds	15.9	4608	3456	1080/60i	21.2	11.3	655	60
12.		Panasonic GM5	Four Thirds	15.8	4592	3448	1080/60p	22.1	11.7	721	66
13.		Panasonic GX1	Four Thirds	15.8	4592	3448	1080/60p	20.8	10.6	703	55
14.		Panasonic GX7	Four Thirds	15.8	4592	3448	1080/60p	22.6	12.2	718	70

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, and both provide the same movie specifications (1080/60i).

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the G3 has an electronic viewfinder (1440k 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 G3, 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 G3	1440	n	3.0 / 460	swivel	Y	1/4000s	4.0/s	Y	n
2.		Panasonic GM1	none	n	3.0 / 1036	fixed	Y	1/500s	5.0/s	Y	n
3.		Panasonic G1	1440	n	3.0 / 460	swivel	n	1/4000s	3.0/s	Y	n
4.		Panasonic G2	1440	n	3.0 / 460	swivel	Y	1/4000s	2.6/s	Y	n
5.		Panasonic G5	1440	n	3.0 / 920	swivel	Y	1/4000s	6.0/s	Y	n
6.		Panasonic G6	1440	n	3.0 / 1036	swivel	Y	1/4000s	7.0/s	Y	n
7.		Panasonic G10	202	n	3.0 / 460	fixed	n	1/4000s	2.6/s	Y	n
8.		Panasonic GF2	optional	n	3.0 / 460	fixed	Y	1/4000s	2.6/s	Y	n
9.		Panasonic GF3	none	n	3.0 / 460	fixed	Y	1/4000s	3.2/s	Y	n
10.		Panasonic GF6	none	n	3.0 / 1040	tilting	Y	1/4000s	4.2/s	Y	n
11.		Panasonic GH2	1534	n	3.0 / 460	swivel	n	1/4000s	3.0/s	Y	n
12.		Panasonic GM5	1166	n	3.0 / 921	fixed	Y	1/500s	5.8/s	n	n
13.		Panasonic GX1	optional	n	3.0 / 460	fixed	Y	1/4000s	4.2/s	Y	n
14.		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.

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, the GM1 is one of those camera that have an additional 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 GM1 has 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 G3 and the GM1 write their files to SDXC cards. The GM1 supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the G3 cannot take advantage of Ultra High Speed SD 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 Panasonic Lumix DMC-G3 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 G3	Y	stereo / mono	-	-	mini	2.0	-	-	-
2.		Panasonic GM1	-	stereo / mono	-	-	micro	2.0	Y	-	-
3.		Panasonic G1	Y	- / -	-	-	mini	2.0	-	-	-
4.		Panasonic G2	Y	stereo / mono	-	-	mini	2.0	-	-	-
5.		Panasonic G5	Y	stereo / mono	-	-	mini	2.0	-	-	-
6.		Panasonic G6	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
7.		Panasonic G10	Y	mono / -	-	-	mini	2.0	-	-	-
8.		Panasonic GF2	Y	stereo / mono	-	-	mini	2.0	-	-	-
9.		Panasonic GF3	-	stereo / mono	-	-	mini	2.0	-	-	-
10.		Panasonic GF6	-	stereo / mono	-	-	mini	2.0	Y	Y	-
11.		Panasonic GH2	Y	stereo / mono	Y	-	mini	2.0	-	-	-
12.		Panasonic GM5	Y	stereo / mono	-	-	micro	2.0	Y	-	-
13.		Panasonic GX1	Y	stereo / mono	-	-	mini	2.0	-	-	-
14.		Panasonic GX7	Y	stereo / mono	-	-	mini	2.0	Y	Y	-

It is notable that the G3 has a hotshoe, while the GM1 does not. This socket makes it possible to easily attach optional accessories, such as an external flash gun.

Both the G3 and the GM1 have been discontinued, but can regularly be found used on ebay. The G3 was replaced by the Panasonic G5, while the GM1 was followed by the Panasonic GM5. Further information on the features and operation of the G3 and GM1 can be found, respectively, in the Panasonic G3 Manual (free pdf) or the online Panasonic GM1 Manual.

Review summary

So what conclusions can be drawn? Which of the two cameras – the Panasonic G3 or the Panasonic GM1 – has the upper hand? Is one clearly better than the other? The listing below highlights the relative strengths of the two models.

Reasons to prefer the Panasonic Lumix DMC-G3:

• 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.
• Longer lasting: Can take more shots (270 versus 230) on a single battery charge.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
• More affordable: Was introduced into a lower priced segment (20 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in May 2011).

Arguments in favor of the Panasonic Lumix DMC-GM1:

• Better image quality: Scores markedly higher (10 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (1.3 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (1.1 EV of extra DR).
• More detailed LCD: Has a higher resolution rear screen (1036k vs 460k dots).
• Faster burst: Shoots at higher frequency (5 vs 4 flaps/sec) to capture the decisive moment.
• Less disturbing: Has an electronic shutter option for completely silent shooting.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• More compact: Is smaller (99x55mm vs 115x84mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 132g or 39 percent) and is thus easier to take along.
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More modern: Reflects 2 years and 5 months of technical progress since the G3 launch.

If the count of individual advantages (bullet points above) is taken as a guide, the GM1 is the clear winner of the contest (12 : 8 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 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 G3 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 incomplete and does no justice, for example, to the way the G3 or the GM1 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 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 G3	3/5	+ +	..	75/100	4.5/5	5/5	May 2011	US$ 599	ebay.com
2.		Panasonic GM1	3/5	+	..	78/100	5/5	4.5/5	Oct 2013	US$ 749	ebay.com
3.		Panasonic G1	..	+ +	..	70/100	4/5	4.5/5	Sep 2008	US$ 599	ebay.com
4.		Panasonic G2	..	..	..	72/100	4/5	4.5/5	Mar 2010	US$ 599	ebay.com
5.		Panasonic G5	3/5	+ +	..	..	4.5/5	4.5/5	Jul 2012	US$ 599	ebay.com
6.		Panasonic G6	4/5	+ +	..	..	5/5	4.5/5	Apr 2013	US$ 599	ebay.com
7.		Panasonic G10	3/5	..	..	70/100	4/5	4/5	Mar 2010	US$ 499	ebay.com
8.		Panasonic GF2	3/5	82/100	..	70/100	4.5/5	4.5/5	Nov 2010	US$ 549	ebay.com
9.		Panasonic GF3	3/5	82/100	..	71/100	4.5/5	4/5	Jun 2011	US$ 549	ebay.com
10.		Panasonic GF6	..	+ +	..	..	4.5/5	4.5/5	Apr 2013	US$ 499	ebay.com
11.		Panasonic GH2	5/5	+ +	..	79/100	4.5/5	5/5	Sep 2010	US$ 899	ebay.com
12.		Panasonic GM5	3.5/5	+	..	77/100	5/5	4.5/5	Sep 2014	US$ 749	ebay.com
13.		Panasonic GX1	3/5	+	..	77/100	4.5/5	4.5/5	Nov 2011	US$ 699	ebay.com
14.		Panasonic GX7	4/5	+	..	79/100	5/5	5/5	Aug 2013	US$ 999	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted with care, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. 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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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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