Canon 20D vs Panasonic G3

The Canon EOS 20D and the Panasonic Lumix DMC-G3 are two digital cameras that were revealed to the public, respectively, in August 2004 and May 2011. The 20D is a DSLR, while the G3 is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (20D) and a Four Thirds (G3) sensor. The Canon has a resolution of 8.2 megapixels, whereas the Panasonic 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

Canon 20D		Panasonic G3
Digital single lens reflex		Mirrorless system camera
Canon EF mount lenses		Micro Four Thirds lenses
8.2 MP – APS-C sensor		15.8 MP – Four Thirds sensor
no Video		1080/60i Video
ISO 100-1,600 (100 - 3,200)		ISO 160-6,400
Optical viewfinder		Electronic viewfinder (1440k dots)
1.8" LCD – 118k dots		3.0" LCD – 460k dots
Fixed screen (not touch-sensitive)		Swivel touchscreen
5 shutter flaps per second		4 shutter flaps per second
700 shots per battery charge		270 shots per battery charge
144 x 106 x 72 mm, 770 g		115 x 84 x 47 mm, 336 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Canon EOS 20D and the Panasonic Lumix DMC-G3? 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 Canon 20D and the Panasonic G3 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 size dimensions are rounded to the nearest millimeter.

The G3 can be obtained in four different colors (black, brown, red, white), while the 20D 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 G3 is considerably smaller (37 percent) than the Canon 20D. Moreover, the G3 is substantially lighter (56 percent) than the 20D. In this context, it is worth noting that neither the 20D nor the G3 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. 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 Canon EF Lens Catalog (20D) and the Micro Four Thirds Lens Catalog (G3). Mirrorless cameras, such as the G3, have moreover the advantage that they can use many lenses from other systems via adapters, as they have a relatively short flange to focal plane distance.

Concerning battery life, the 20D gets 700 shots out of its Canon BP-511A battery, while the G3 can take 270 images on a single charge of its Panasonic DMW-BLD10 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.		Canon 20D	144 mm	106 mm	72 mm	770 g	700	n	Aug 2004	1,499	ebay.com
2.		Panasonic G3	115 mm	84 mm	47 mm	336 g	270	n	May 2011	599	ebay.com
3.		Canon 7D II	149 mm	112 mm	78 mm	910 g	670	Y	Sep 2014	1,799	ebay.com
4.		Canon 60D	145 mm	106 mm	79 mm	755 g	1100	Y	Aug 2010	1,399	ebay.com
5.		Canon 7D	148 mm	111 mm	74 mm	860 g	800	Y	Sep 2009	1,699	ebay.com
6.		Canon 50D	146 mm	108 mm	74 mm	822 g	800	Y	Aug 2008	1,299	ebay.com
7.		Canon 40D	146 mm	108 mm	74 mm	822 g	750	n	Aug 2007	1,299	ebay.com
8.		Canon 30D	144 mm	106 mm	74 mm	785 g	750	n	Feb 2006	1,399	ebay.com
9.		Canon XT	127 mm	94 mm	64 mm	540 g	400	n	Feb 2005	899	ebay.com
10.		Canon 10D	150 mm	107 mm	75 mm	850 g	500	n	Feb 2003	1,999	ebay.com
11.		Canon Rebel	142 mm	99 mm	72 mm	649 g	400	n	Aug 2003	899	ebay.com
12.		Nikon D200	147 mm	113 mm	74 mm	920 g	400	Y	Nov 2005	1,699	ebay.com
13.		Panasonic G6	122 mm	85 mm	71 mm	390 g	340	n	Apr 2013	599	ebay.com
14.		Panasonic G5	120 mm	83 mm	71 mm	396 g	320	n	Jul 2012	599	ebay.com
15.		Panasonic GX1	116 mm	68 mm	39 mm	318 g	320	n	Nov 2011	699	ebay.com
16.		Panasonic G2	124 mm	84 mm	74 mm	428 g	360	n	Mar 2010	599	ebay.com
17.		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

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 G3 was launched at a markedly lower price (by 60 percent) than the 20D, 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 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Canon 20D features an APS-C sensor and the Panasonic G3 a Four Thirds sensor. The sensor area in the G3 is 33 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.6 and 2.0. The sensor in the 20D has a native 3:2 aspect ratio, while the one in the G3 offers a 4:3 aspect.

Despite having a smaller sensor, the G3 offers a higher resolution of 15.8 megapixels, compared with 8.2 MP of the 20D. 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 3.77μm versus 6.42μm for the 20D). However, it should be noted that the G3 is much more recent (by 6 years and 8 months) than the 20D, and its sensor will have benefitted from technological advances during this time that make it possible to gather light more efficiently.

The resolution advantage of the Panasonic G3 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the G3 for good quality output (200 dots per inch) amounts to 23 x 17.2 inches or 58.3 x 43.8 cm, for very good quality (250 dpi) 18.4 x 13.8 inches or 46.7 x 35 cm, and for excellent quality (300 dpi) 15.3 x 11.5 inches or 38.9 x 29.2 cm. The corresponding values for the Canon 20D are 17.5 x 11.7 inches or 44.5 x 29.7 cm for good quality, 14 x 9.3 inches or 35.6 x 23.7 cm for very good quality, and 11.7 x 7.8 inches or 29.7 x 19.8 cm for excellent quality prints.

The Canon EOS 20D has a native sensitivity range from ISO 100 to ISO 1600, which can be extended to ISO 100-3200. The corresponding ISO settings for the Panasonic Lumix DMC-G3 are ISO 160 to ISO 6400 (no boost).

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.

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"). Of the two cameras under review, the 20D has a notably higher overall DXO score than the G3 (overall score 6 points higher), which gives it an advantage in terms of imaging quality. This advantage is based on 0.9 bits higher color depth, 0.4 EV in additional dynamic range, and 0.1 stops in additional 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.		Canon 20D	APS-C	8.2	3504	2336	none	21.9	11.0	721	62
2.		Panasonic G3	Four Thirds	15.8	4592	3448	1080/60i	21.0	10.6	667	56
3.		Canon 7D II	APS-C	20.0	5472	3648	1080/60p	22.4	11.8	1082	70
4.		Canon 60D	APS-C	17.9	5184	3456	1080/30p	22.2	11.5	813	66
5.		Canon 7D	APS-C	17.9	5184	3456	1080/30p	22.0	11.7	854	66
6.		Canon 50D	APS-C	15.1	4752	3168	none	21.8	11.4	696	63
7.		Canon 40D	APS-C	10.1	3888	2592	none	22.1	11.3	703	64
8.		Canon 30D	APS-C	8.2	3504	2336	none	21.5	10.8	736	59
9.		Canon XT	APS-C	8.0	3456	2304	none	21.8	10.8	637	60
10.		Canon 10D	APS-C	6.3	3072	2048	none	21.1	10.9	571	57
11.		Canon Rebel	APS-C	6.3	3072	2048	none	21.0	10.8	544	55
12.		Nikon D200	APS-C	10.0	3872	2592	none	22.3	11.5	583	64
13.		Panasonic G6	Four Thirds	15.9	4608	3456	1080/60p	21.3	11.5	639	61
14.		Panasonic G5	Four Thirds	15.9	4608	3456	1080/60p	21.4	11.6	618	61
15.		Panasonic GX1	Four Thirds	15.8	4592	3448	1080/60p	20.8	10.6	703	55
16.		Panasonic G2	Four Thirds	12.0	4000	3000	720/30p	21.2	10.3	493	53
17.		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. The G3 indeed provides for movie recording, while the 20D does not. The highest resolution format that the G3 can use is 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), while the 20D has an optical one. Both systems have their advantages, with the electronic viewfinder making it possible to project supplementary shooting information into the framing view, whereas the optical viewfinder offers lag-free viewing and a very clear framing image. The viewfinder in the G3 offers a wider field of view (100%) than the one in the 20D (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the G3 has a higher magnification (0.70x vs 0.56x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The adjacent table lists some of the other core features of the Canon 20D and Panasonic G3 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.		Canon 20D	optical	Y	1.8 / 118	fixed	n	1/8000s	5.0/s	Y	n
2.		Panasonic G3	1440	n	3.0 / 460	swivel	Y	1/4000s	4.0/s	Y	n
3.		Canon 7D II	optical	Y	3.0 / 1040	fixed	n	1/8000s	10.0/s	Y	n
4.		Canon 60D	optical	Y	3.0 / 1040	swivel	n	1/8000s	5.3/s	Y	n
5.		Canon 7D	optical	Y	3.0 / 920	fixed	n	1/8000s	8.0/s	Y	n
6.		Canon 50D	optical	Y	3.0 / 920	fixed	n	1/8000s	6.3/s	Y	n
7.		Canon 40D	optical	Y	3.0 / 230	fixed	n	1/8000s	6.5/s	Y	n
8.		Canon 30D	optical	Y	2.5 / 230	fixed	n	1/8000s	5.0/s	Y	n
9.		Canon XT	optical	n	1.8 / 115	fixed	n	1/4000s	3.0/s	Y	n
10.		Canon 10D	optical	Y	1.8 / 118	fixed	n	1/4000s	3.0/s	Y	n
11.		Canon Rebel	optical	n	1.8 / 118	fixed	n	1/4000s	2.5/s	Y	n
12.		Nikon D200	optical	Y	2.5 / 230	fixed	n	1/8000s	5.0/s	Y	n
13.		Panasonic G6	1440	n	3.0 / 1036	swivel	Y	1/4000s	7.0/s	Y	n
14.		Panasonic G5	1440	n	3.0 / 920	swivel	Y	1/4000s	6.0/s	Y	n
15.		Panasonic GX1	optional	n	3.0 / 460	fixed	Y	1/4000s	4.2/s	Y	n
16.		Panasonic G2	1440	n	3.0 / 460	swivel	Y	1/4000s	2.6/s	Y	n
17.		Panasonic GH2	1534	n	3.0 / 460	swivel	n	1/4000s	3.0/s	Y	n
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that is present on the 20D, but is missing on the G3 is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.

The 20D writes its imaging data to Compact Flash cards, while the G3 uses SDXC 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 Canon EOS 20D and Panasonic Lumix DMC-G3 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.		Canon 20D	Y	- / -	-	-	-	1.1	-	-	-
2.		Panasonic G3	Y	stereo / mono	-	-	mini	2.0	-	-	-
3.		Canon 7D II	Y	stereo / mono	Y	Y	mini	3.0	-	-	-
4.		Canon 60D	Y	mono / mono	Y	-	mini	2.0	-	-	-
5.		Canon 7D	Y	mono / -	Y	-	mini	2.0	-	-	-
6.		Canon 50D	Y	- / -	-	-	mini	2.0	-	-	-
7.		Canon 40D	Y	- / -	-	-	-	2.0	-	-	-
8.		Canon 30D	Y	- / -	-	-	-	2.0	-	-	-
9.		Canon XT	Y	- / -	-	-	-	2.0	-	-	-
10.		Canon 10D	Y	- / -	-	-	-	1.1	-	-	-
11.		Canon Rebel	Y	- / -	-	-	-	1.1	-	-	-
12.		Nikon D200	Y	- / -	-	-	-	2.0	-	-	-
13.		Panasonic G6	Y	stereo / mono	Y	-	mini	2.0	Y	Y	-
14.		Panasonic G5	Y	stereo / mono	-	-	mini	2.0	-	-	-
15.		Panasonic GX1	Y	stereo / mono	-	-	mini	2.0	-	-	-
16.		Panasonic G2	Y	stereo / mono	-	-	mini	2.0	-	-	-
17.		Panasonic GH2	Y	stereo / mono	Y	-	mini	2.0	-	-	-

Studio photographers will appreciate that the Canon 20D (unlike the G3) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the 20D and the G3 have been discontinued, but can regularly be found used on ebay. The 20D was replaced by the Canon 30D, while the G3 was followed by the Panasonic G5. Further information on the features and operation of the 20D and G3 can be found, respectively, in the Canon 20D Manual (free pdf) or the online Panasonic G3 Manual.

Review summary

So how do things add up? Which of the two cameras – the Canon 20D or the Panasonic G3 – has the upper hand? Is one clearly better than the other? The listing below highlights the relative strengths of the two models.

Advantages of the Canon EOS 20D:

• Better image quality: Scores markedly higher (6 points) in the DXO overall assessment.
• Brighter framing: Features an optical viewfinder for clear, lag-free composition.
• Easier setting verification: Features an LCD display on top to control shooting parameters.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (5 vs 4 flaps/sec) to capture the decisive moment.
• Longer lasting: Can take more shots (700 versus 270) on a single battery charge.
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• More heavily discounted: Has been available for much longer (launched in August 2004).

Arguments in favor of the Panasonic Lumix DMC-G3:

• More detail: Has more megapixels (15.8 vs 8.2MP), which boosts linear resolution by 36%.
• Broader imaging potential: Can capture not only stills but also 1080/60i video.
• More framing info: Has an electronic viewfinder that displays shooting data.
• More complete view: Has a viewfinder with a larger field of view (100% vs 95%).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.70x vs 0.56x).
• Larger screen: Has a bigger rear LCD (3.0" vs 1.8") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (460k vs 118k dots).
• More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
• Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• More compact: Is smaller (115x84mm vs 144x106mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 434g or 56 percent) and is thus easier to take along.
• More legacy lens friendly: Can use many non-native lenses via adapters.
• Faster data transfer: Supports a more advanced USB protocol (2.0 vs 1.1).
• More affordable: Was introduced into a lower priced category (60 percent cheaper at launch).
• More modern: Reflects 6 years and 8 months of technical progress since the 20D launch.

If the count of relative strengths (bullet points above) is taken as a measure, the G3 is the clear winner of the contest (16 : 8 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 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 Canon 20D and the Panasonic G3 place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Mirrorless Interchangeable Lens Camera listings 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 remains incomplete and does no justice, for example, to the way the 20D or the G3 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 (USD)	Street Price
1.		Canon 20D	..	..	..	+ +	..	..	Aug 2004	1,499	ebay.com
2.		Panasonic G3	3/5	+ +	..	75/100	4.5/5	5/5	May 2011	599	ebay.com
3.		Canon 7D II	4.5/5	+	3.5/5	84/100	4/5	4.5/5	Sep 2014	1,799	ebay.com
4.		Canon 60D	5/5	+	..	79/100	4/5	4.5/5	Aug 2010	1,399	ebay.com
5.		Canon 7D	5/5	+ +	..	84/100	4.5/5	4.5/5	Sep 2009	1,699	ebay.com
6.		Canon 50D	..	+ +	..	+ +	4.5/5	4.5/5	Aug 2008	1,299	ebay.com
7.		Canon 40D	..	+ +	..	+ +	4.5/5	4.5/5	Aug 2007	1,299	ebay.com
8.		Canon 30D	..	+ +	..	+ +	o	..	Feb 2006	1,399	ebay.com
9.		Canon XT	..	80/100	..	+ +	o	..	Feb 2005	899	ebay.com
10.		Canon 10D	..	..	..	+ +	..	..	Feb 2003	1,999	ebay.com
11.		Canon Rebel	..	..	..	+ +	..	..	Aug 2003	899	ebay.com
12.		Nikon D200	..	+ +	..	+ +	o	..	Nov 2005	1,699	ebay.com
13.		Panasonic G6	4/5	+ +	..	..	5/5	4.5/5	Apr 2013	599	ebay.com
14.		Panasonic G5	3/5	+ +	..	..	4.5/5	4.5/5	Jul 2012	599	ebay.com
15.		Panasonic GX1	3/5	+	..	77/100	4.5/5	4.5/5	Nov 2011	699	ebay.com
16.		Panasonic G2	..	..	..	72/100	4/5	4.5/5	Mar 2010	599	ebay.com
17.		Panasonic GH2	5/5	+ +	..	79/100	4.5/5	5/5	Sep 2010	899	ebay.com
Note: (+ +) 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

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. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.

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