Canon G7 X Mark III vs Olympus E-P3

The Canon PowerShot G7 X Mark III and the Olympus PEN E-P3 are two digital cameras that were announced, respectively, in July 2019 and June 2011. The G7X Mark III is a fixed lens compact, while the E-P3 is a mirrorless interchangeable lens camera. The cameras are based on an one-inch (G7X Mark III) and a Four Thirds (E-P3) sensor. The Canon has a resolution of 20 megapixels, whereas the Olympus provides 12.2 MP.

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

Headline Specifications

Canon G7 X Mark III		Olympus E-P3
Fixed lens compact camera		Mirrorless system camera
24-100mm f/1.8-2.8		Micro Four Thirds lenses
20 MP – 1" sensor		12.2 MP – Four Thirds sensor
4K/30p Video		1080/60i Video
ISO 125-12,800 (125 - 25,600)		ISO 200-12,800
No viewfinder, LCD framing		Viewfinder optional
3.0" LCD – 1040k dots		3.0" LCD – 614k dots
Tilting touchscreen		Fixed touchscreen
30 shutter flaps per second		3 shutter flaps per second
Lens-based stabilization		In-body stabilization
235 shots per battery charge		330 shots per battery charge
105 x 61 x 41 mm, 304 g		122 x 69 x 34 mm, 369 g

Check G7X Mark III price at
amazon.com
Check E-P3 offers at
ebay.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Canon PowerShot G7 X Mark III and the Olympus PEN E-P3? 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 Canon G7 X Mark III and the Olympus E-P3. 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 G7X Mark III can be obtained in two different colors (black, silver), while the E-P3 is available in three color-versions (black, silver, white).

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Olympus E-P3 is notably larger (31 percent) than the Canon G7 X Mark III. In this context, it is worth noting that neither the G7X Mark III nor the E-P3 are weather-sealed.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the G7X Mark III has a lens built in, whereas the E-P3 is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup. You can compare the optics available for the E-P3 and their specifications in the Micro Four Thirds Lens Catalog.

Concerning battery life, the G7X Mark III gets 235 shots out of its Canon NB-13L battery, while the E-P3 can take 330 images on a single charge of its Olympus BLS-5 power pack. The power pack in the G7X Mark III can be charged via the USB port, so that it is not always necessary to take the battery charger along when travelling.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. In case you want to display and compare another camera duo, you can use the CAM-parator app to select your camera combination among a large number of options.

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 G7 X Mark III	105 mm	61 mm	41 mm	304 g	235	n	Jul 2019	749	amazon.com
2.		Olympus E-P3	122 mm	69 mm	34 mm	369 g	330	n	Jun 2011	799	ebay.com
3.		Canon G5 X	112 mm	76 mm	44 mm	353 g	210	n	Oct 2015	799	ebay.com
4.		Canon G5 X Mark II	111 mm	61 mm	46 mm	340 g	230	n	Jul 2019	899	ebay.com
5.		Canon G7 X	103 mm	60 mm	40 mm	304 g	210	n	Sep 2014	699	ebay.com
6.		Canon G7 X Mark II	106 mm	61 mm	42 mm	319 g	265	n	Feb 2016	699	ebay.com
7.		Canon SX740	110 mm	64 mm	40 mm	299 g	265	n	Jul 2018	399	amazon.com
8.		Leica C-LUX	113 mm	67 mm	46 mm	340 g	370	n	Jun 2018	1,049	ebay.com
9.		Olympus E-P1	121 mm	70 mm	36 mm	355 g	300	n	Jun 2009	799	ebay.com
10.		Olympus E-P2	121 mm	70 mm	36 mm	355 g	300	n	Nov 2009	799	ebay.com
11.		Olympus E-PL1	115 mm	72 mm	42 mm	334 g	290	n	Feb 2010	599	ebay.com
12.		Olympus E-PL2	114 mm	72 mm	42 mm	362 g	280	n	Jan 2011	599	ebay.com
13.		Olympus E-PL3	110 mm	64 mm	37 mm	313 g	300	n	Jun 2011	599	ebay.com
14.		Panasonic FZ1000 II	136 mm	97 mm	131 mm	810 g	350	n	Feb 2019	899	amazon.com
15.		Panasonic ZS200	111 mm	65 mm	45 mm	340 g	370	n	Feb 2018	799	amazon.com
16.		Sony RX100 VI	102 mm	58 mm	43 mm	301 g	240	n	Jun 2018	1,199	ebay.com
17.		Sony ZV-1	105 mm	60 mm	44 mm	294 g	260	n	May 2020	799	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 G7X Mark III was launched at a lower price than the E-P3, despite having a lens built in. 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. All other things equal, a large sensor will have larger individual pixel-units that offer better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixels 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.

Of the two cameras under consideration, the Canon G7 X Mark III features an one-inch sensor and the Olympus E-P3 a Four Thirds sensor. The sensor area in the E-P3 is 94 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.7 and 2.0. The sensor in the G7X Mark III has a native 3:2 aspect ratio, while the one in the E-P3 offers a 4:3 aspect.

Despite having a smaller sensor, the Canon G7 X Mark III offers a higher resolution of 20 megapixels, compared with 12.2 MP of the Olympus E-P3. 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 2.41μm versus 4.29μm for the E-P3). However, it should be noted that the G7X Mark III is much more recent (by 8 years) than the E-P3, 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 Canon G7 X Mark III implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the G7X Mark III for good quality output (200 dots per inch) amounts to 27.4 x 18.2 inches or 69.5 x 46.3 cm, for very good quality (250 dpi) 21.9 x 14.6 inches or 55.6 x 37.1 cm, and for excellent quality (300 dpi) 18.2 x 12.2 inches or 46.3 x 30.9 cm. The corresponding values for the Olympus E-P3 are 20.2 x 15.1 inches or 51.2 x 38.4 cm for good quality, 16.1 x 12.1 inches or 41 x 30.7 cm for very good quality, and 13.4 x 10.1 inches or 34.1 x 25.6 cm for excellent quality prints.

The Canon PowerShot G7 X Mark III has a native sensitivity range from ISO 125 to ISO 12800, which can be extended to ISO 125-25600. The corresponding ISO settings for the Olympus PEN E-P3 are ISO 200 to ISO 12800 (no boost).

In terms of underlying technology, the G7X Mark III is build around a BSI-CMOS sensor, while the E-P3 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.

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 following table provides an overview of the physical sensor characteristics, as well as the sensor quality measurements for a selection of comparators.

Sensor Characteristics

		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Canon G7 X Mark III	1-inch	20.0	5472	3648	4K/30p	22.2	12.4	583	65
2.		Olympus E-P3	Four Thirds	12.2	4032	3024	1080/60i	20.8	10.1	536	51
3.		Canon G5 X	1-inch	20.0	5472	3648	1080/60p	21.4	12.3	471	62
4.		Canon G5 X Mark II	1-inch	20.0	5472	3648	4K/30p	22.2	12.4	583	65
5.		Canon G7 X	1-inch	20.0	5472	3648	1080/60p	23.0	12.7	556	71
6.		Canon G7 X Mark II	1-inch	20.0	5472	3648	1080/60p	21.8	11.9	260	62
7.		Canon SX740	1/2.3	20.2	5184	3888	4K/30p	20.6	12.1	1050	51
8.		Leica C-LUX	1-inch	20.0	5472	3648	4K/30p	22.1	12.3	481	64
9.		Olympus E-P1	Four Thirds	12.2	4032	3024	720/30p	21.4	10.4	536	55
10.		Olympus E-P2	Four Thirds	12.2	4032	3024	720/30p	21.5	10.4	505	56
11.		Olympus E-PL1	Four Thirds	12.2	4032	3024	720/30p	21.5	10.1	487	54
12.		Olympus E-PL2	Four Thirds	12.2	4032	3024	720/30p	21.4	10.2	573	55
13.		Olympus E-PL3	Four Thirds	12.2	4032	3024	1080/60i	20.9	10.3	499	52
14.		Panasonic FZ1000 II	1-inch	20.0	5472	3648	4K/30p	22.1	12.4	546	65
15.		Panasonic ZS200	1-inch	20.0	5472	3648	4K/30p	22.0	12.2	449	64
16.		Sony RX100 VI	1-inch	20.0	5472	3648	4K/30p	22.1	12.3	478	64
17.		Sony ZV-1	1-inch	20.0	5472	3648	4K/30p	22.2	12.6	669	66
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. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the G7X Mark III provides a higher video resolution than the E-P3. It can shoot video footage at 4K/30p, while the Olympus is limited to 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The G7X Mark III and the E-P3 are similar in the sense that neither of the two has a viewfinder. The images are, thus, framed using live view on the rear LCD. That said, the E-P3 can be equipped with an optional viewfinder – the VF-3. The following table reports on some other key feature differences and similarities of the Canon G7 X Mark III, the Olympus E-P3, 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.		Canon G7 X Mark III	none	n	3.0 / 1040	tilting	Y	1/2000s	30/s	Y	Y
2.		Olympus E-P3	optional	n	3.0 / 614	fixed	Y	1/4000s	3.0/s	Y	Y
3.		Canon G5 X	2360	n	3.0 / 1040	swivel	Y	1/2000s	5.9/s	Y	Y
4.		Canon G5 X Mark II	2360	n	3.0 / 1040	tilting	Y	1/2000s	30/s	Y	Y
5.		Canon G7 X	none	n	3.0 / 1040	tilting	Y	1/2000s	6.5/s	Y	Y
6.		Canon G7 X Mark II	none	n	3.0 / 1040	tilting	Y	1/2000s	8.0/s	Y	Y
7.		Canon SX740	none	n	3.0 / 922	tilting	n	1/3200s	10.0/s	Y	Y
8.		Leica C-LUX	2330	n	3.0 / 1240	fixed	Y	1/2000s	10.0/s	Y	Y
9.		Olympus E-P1	none	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	Y
10.		Olympus E-P2	optional	n	3.0 / 230	fixed	n	1/4000s	3.0/s	n	Y
11.		Olympus E-PL1	optional	n	2.7 / 230	fixed	n	1/2000s	3.0/s	Y	Y
12.		Olympus E-PL2	optional	n	3.0 / 460	fixed	n	1/4000s	3.0/s	Y	Y
13.		Olympus E-PL3	optional	n	3.0 / 460	tilting	n	1/4000s	5.5/s	n	Y
14.		Panasonic FZ1000 II	2360	n	3.0 / 1240	swivel	Y	1/4000s	12.0/s	Y	Y
15.		Panasonic ZS200	2330	n	3.0 / 1240	fixed	Y	1/2000s	10.0/s	Y	Y
16.		Sony RX100 VI	2359	n	3.0 / 1229	tilting	Y	1/2000s	24.0/s	Y	Y
17.		Sony ZV-1	none	n	3.0 / 922	swivel	Y	1/2000s	24.0/s	n	n
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 G7X Mark III 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 Canon G7 X Mark III 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 G7X Mark III and the E-P3 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 Canon PowerShot G7 X Mark III and Olympus PEN E-P3 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 G7 X Mark III	-	stereo / mono	Y	-	micro	3.1	Y	-	Y
2.		Olympus E-P3	Y	stereo / -	-	-	mini	2.0	-	-	-
3.		Canon G5 X	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
4.		Canon G5 X Mark II	-	stereo / mono	-	-	micro	3.1	Y	-	Y
5.		Canon G7 X	-	stereo / mono	-	-	micro	2.0	Y	Y	-
6.		Canon G7 X Mark II	-	stereo / mono	-	-	micro	2.0	Y	Y	-
7.		Canon SX740	-	stereo / mono	-	-	micro	2.0	Y	-	Y
8.		Leica C-LUX	-	stereo / mono	-	-	micro	2.0	Y	-	-
9.		Olympus E-P1	Y	stereo / -	-	-	mini	2.0	-	-	-
10.		Olympus E-P2	Y	stereo / -	-	-	mini	2.0	-	-	-
11.		Olympus E-PL1	Y	stereo / -	-	-	mini	2.0	-	-	-
12.		Olympus E-PL2	Y	stereo / -	-	-	mini	2.0	-	-	-
13.		Olympus E-PL3	Y	stereo / -	-	-	mini	2.0	-	-	-
14.		Panasonic FZ1000 II	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y
15.		Panasonic ZS200	-	stereo / mono	-	-	micro	2.0	Y	-	Y
16.		Sony RX100 VI	-	stereo / mono	-	-	micro	2.0	Y	Y	Y
17.		Sony ZV-1	Y	stereo / mono	Y	-	micro	2.0	Y	-	Y

It is notable that the G7X Mark III has a microphone port, which is missing on the E-P3. Such an external microphone input can help to substantially improve the quality of audio recordings when a good external microphone is used.

The G7X Mark III is a recent model that features in the current product line-up of Canon. In contrast, the E-P3 has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the E-P3 was succeeded by the Olympus E-P5. Further information on the features and operation of the G7X Mark III and E-P3 can be found, respectively, in the Canon G7 X Mark III Manual (free pdf) or the online Olympus E-P3 Manual.

Review summary

So what is the bottom line? Is the Canon G7 X Mark III better than the Olympus E-P3 or vice versa? Below is a summary of the relative strengths of each of the two contestants.

Arguments in favor of the Canon PowerShot G7 X Mark III:

• More detail: Offers more megapixels (20 vs 12.2MP) with a 30% higher linear resolution.
• Better video: Provides higher definition movie capture (4K/30p vs 1080/60i).
• Better sound: Can connect to an external microphone for higher quality sound recording.
• More detailed LCD: Has a higher resolution rear screen (1040k vs 614k dots).
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Faster burst: Shoots at higher frequency (30 vs 3 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.
• Ready to shoot: Has a lens built-in, whereas the E-P3 requires a separate lens.
• More compact: Is smaller (105x61mm vs 122x69mm) and thus needs less room in the bag.
• Less heavy: Is lighter even though it comes with a built-in lens (unlike the E-P3).
• Easier travel charging: Can be conveniently charged via its USB port.
• Faster data transfer: Supports a more advanced USB protocol (3.1 vs 2.0).
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Easier wireless transfer: Supports Bluetooth for image sharing without cables.
• More affordable: Was introduced at a lower price, despite coming with a built-in lens.
• More modern: Reflects 8 years of technical progress since the E-P3 launch.

Reasons to prefer the Olympus PEN E-P3:

• More framing options: Can be equipped with a hotshoe-mounted accessory-viewfinder.
• Faster shutter: Has higher mechanical shutter speed (1/4000s vs 1/2000s) to freeze action.
• More flexible: Takes interchangeable lenses and can thus be used with specialty optics.
• Longer lasting: Gets more shots (330 versus 235) out of a single battery charge.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
• More heavily discounted: Has been around for much longer (launched in June 2011).

If the number of relative strengths (bullet points above) is taken as a guide, the G7X Mark III is the clear winner of the match-up (18 : 6 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 Canon G7 X Mark III and the Olympus E-P3 place the cameras among the top in their class? Find out in the latest Best Travel-Zoom Camera and Best Mirrorless Interchangeable Lens Camera listings 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 G7X Mark III or the E-P3 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 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 G7 X Mark III	..	+ +	4/5	81/100	4/5	..	Jul 2019	749	amazon.com
2.		Olympus E-P3	..	83/100	..	74/100	4.5/5	4.5/5	Jun 2011	799	ebay.com
3.		Canon G5 X	5/5	+ +	..	78/100	4.5/5	4.5/5	Oct 2015	799	ebay.com
4.		Canon G5 X Mark II	4/5	+	4/5	82/100	..	4/5	Jul 2019	899	ebay.com
5.		Canon G7 X	4/5	+ +	..	77/100	4.5/5	4.5/5	Sep 2014	699	ebay.com
6.		Canon G7 X Mark II	4.5/5	+ +	..	81/100	4.5/5	4.5/5	Feb 2016	699	ebay.com
7.		Canon SX740	..	+	3.5/5	..	4/5	4/5	Jul 2018	399	amazon.com
8.		Leica C-LUX	..	..	3.5/5	..	4.5/5	4/5	Jun 2018	1,049	ebay.com
9.		Olympus E-P1	..	+	..	66/100	4/5	4.5/5	Jun 2009	799	ebay.com
10.		Olympus E-P2	3/5	+	..	69/100	4/5	4.5/5	Nov 2009	799	ebay.com
11.		Olympus E-PL1	..	86/100	..	69/100	4/5	4.5/5	Feb 2010	599	ebay.com
12.		Olympus E-PL2	3/5	83/100	..	71/100	4.5/5	4.5/5	Jan 2011	599	ebay.com
13.		Olympus E-PL3	3/5	+ +	..	72/100	4.5/5	4/5	Jun 2011	599	ebay.com
14.		Panasonic FZ1000 II	..	..	..	83/100	4.5/5	4.5/5	Feb 2019	899	amazon.com
15.		Panasonic ZS200	..	+ +	4.5/5	81/100	4.5/5	4.5/5	Feb 2018	799	amazon.com
16.		Sony RX100 VI	4.5/5	+ +	..	83/100	4/5	4.5/5	Jun 2018	1,199	ebay.com
17.		Sony ZV-1	4/5	+	4/5	85/100	4/5	4.5/5	May 2020	799	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. 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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