Olympus E-M5 III vs Sony A7C

The Olympus OM-D E-M5 Mark III and the Sony Alpha A7C are two enthusiast cameras that were officially introduced, respectively, in October 2019 and September 2020. Both the E-M5 III and the A7C are mirrorless interchangeable lens cameras that are based on a Four Thirds (E-M5 III) and a full frame (A7C) sensor. The Olympus has a resolution of 20.2 megapixels, whereas the Sony provides 24 MP.

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

Headline Specifications

Olympus E-M5 III		Sony A7C
Mirrorless system camera		Mirrorless system camera
Micro Four Thirds lenses		Sony E mount lenses
20.2 MP, Four Thirds Sensor		24 MP, Full Frame Sensor
4K/30p Video		4K/30p Video
ISO 200-25,600		ISO 100-51,200 (50 - 204,800)
Electronic viewfinder (2360k dots)		Electronic viewfinder (2360k dots)
3.0 LCD, 1040k dots		3.0 LCD, 922k dots
Swivel touchscreen		Swivel touchscreen
10 shutter flaps per second		10 shutter flaps per second
In-body stabilization		In-body stabilization
Weathersealed body		Weathersealed body
310 shots per battery charge		740 shots per battery charge
125 x 85 x 50 mm, 414 g		124 x 71 x 60 mm, 509 g

Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus OM-D E-M5 Mark III and the Sony Alpha A7C? 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 Olympus E-M5 III and the Sony A7C 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 measures are rounded to the nearest millimeter.

Both cameras are available in two different colors (black, silver).

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7C is notably smaller (17 percent) than the Olympus E-M5 III. However, the A7C is markedly heavier (23 percent) than the E-M5 III. 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. 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 Micro Four Thirds Lens Catalog (E-M5 III) and the Sony FE Lens Catalog (A7C). 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 E-M5 III gets 310 shots out of its BLS-50 battery, while the A7C can take 740 images on a single charge of its NP-FZ100 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 (USD)	Street Price
1.		Olympus E-M5 III	125 mm	85 mm	50 mm	414 g	310	Y	Oct 2019	1,199
2.		Sony A7C	124 mm	71 mm	60 mm	509 g	740	Y	Sep 2020	1,799
3.		Olympus E-M1 III	134 mm	91 mm	69 mm	580 g	420	Y	Feb 2020	1,799
4.		Olympus E-M10 IV	122 mm	84 mm	49 mm	383 g	360	n	Aug 2020	699
5.		Olympus E-M1X	144 mm	147 mm	75 mm	997 g	870	Y	Jan 2019	2,999
6.		Olympus E-M1 II	134 mm	91 mm	67 mm	574 g	440	Y	Sep 2016	1,999
7.		Olympus PEN-F	125 mm	72 mm	37 mm	427 g	330	n	Jan 2016	1,199
8.		Olympus E-M5 II	124 mm	85 mm	45 mm	469 g	310	Y	Feb 2015	1,099
9.		Olympus E-M1	130 mm	94 mm	63 mm	497 g	350	Y	Sep 2013	1,399
10.		Olympus E-M5	122 mm	89 mm	43 mm	425 g	360	Y	Feb 2012	1,299
11.		Panasonic G90	130 mm	94 mm	77 mm	536 g	290	Y	Apr 2019	999
12.		Panasonic GX8	133 mm	78 mm	63 mm	487 g	330	Y	Jul 2015	1,199
13.		Sony A6600	120 mm	67 mm	69 mm	503 g	810	Y	Aug 2019	1,399
14.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	4,499
15.		Sony A6500	120 mm	67 mm	53 mm	453 g	350	Y	Oct 2016	1,399
16.		Sony A7 II	127 mm	96 mm	60 mm	599 g	350	Y	Nov 2014	1,999
17.		Sony A7	127 mm	94 mm	48 mm	474 g	340	Y	Oct 2013	1,699
Notes: 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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The E-M5 III was launched at a markedly lower price (by 33 percent) than the A7C, which puts it into a different market segment. 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.

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. 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. 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.

Of the two cameras under consideration, the Olympus E-M5 III features a Four Thirds sensor and the Sony A7C a full frame sensor. The sensor area in the A7C is 276 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 1.0. The sensor in the E-M5 III has a native 4:3 aspect ratio, while the one in the A7C offers a 3:2 aspect.

With 24MP, the A7C offers a higher resolution than the E-M5 III (20.2MP), but the A7C nevertheless has larger individual pixels (pixel pitch of 5.94μm versus 3.34μm for the E-M5 III) due to its larger sensor. Moreover, the A7C is a somewhat more recent model (by 10 months) than the E-M5 III, and its sensor might have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixel-units. Coming back to sensor resolution, it should be mentioned that the E-M5 III has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Sony A7C implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A7C for good quality output (200 dots per inch) amounts to 30 x 20 inches or 76.2 x 50.8 cm, for very good quality (250 dpi) 24 x 16 inches or 61 x 40.6 cm, and for excellent quality (300 dpi) 20 x 13.3 inches or 50.8 x 33.9 cm. The corresponding values for the Olympus E-M5 III 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.

Unlike the A7C, the E-M5 III has the capacity to capture high quality composite images (80MP) by combining multiple shots after shifting its sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).

The Olympus OM-D E-M5 Mark III has a native sensitivity range from ISO 200 to ISO 25600, which can be extended to ISO 64-25600. The corresponding ISO settings for the Sony Alpha A7C are ISO 100 to ISO 51200, with the possibility to increase the ISO range to 50-204800.

For many cameras, data on sensor performance has been reported by DXO Mark. 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. 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.		Olympus E-M5 III	Four Thirds	20.2	5184	3888	4K/30p	..	..	..	..
2.		Sony A7C	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3407	95
3.		Olympus E-M1 III	Four Thirds	20.2	5184	3888	4K/30p	..	..	..	..
4.		Olympus E-M10 IV	Four Thirds	20.2	5184	3888	4K/30p	..	..	..	..
5.		Olympus E-M1X	Four Thirds	20.2	5184	3888	4K/30p	..	..	..	..
6.		Olympus E-M1 II	Four Thirds	20.2	5184	3888	4K/30p	23.7	12.8	1312	80
7.		Olympus PEN-F	Four Thirds	20.2	5184	3888	1080/60p	23.1	12.4	894	74
8.		Olympus E-M5 II	Four Thirds	15.9	4608	3456	1080/60p	23.0	12.5	842	73
9.		Olympus E-M1	Four Thirds	15.9	4608	3456	1080/30p	23.0	12.7	757	73
10.		Olympus E-M5	Four Thirds	15.9	4608	3456	1080/60i	22.8	12.3	826	71
11.		Panasonic G90	Four Thirds	20.2	5184	3888	4K/30p	..	..	..	..
12.		Panasonic GX8	Four Thirds	20.2	5184	3888	4K/30p	23.5	12.6	806	75
13.		Sony A6600	APS-C	24.0	6000	4000	4K/30p	23.8	13.4	1497	82
14.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
15.		Sony A6500	APS-C	24.0	6000	4000	4K/30p	24.5	13.7	1405	85
16.		Sony A7 II	Full Frame	24.0	6000	4000	1080/60p	24.9	13.6	2449	90
17.		Sony A7	Full Frame	24.0	6000	4000	1080/60p	24.8	14.2	2248	90

Many modern cameras are not only capable of taking still images, but also of capturing video footage. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the A7C provides a faster frame rate than the E-M5 III. It can shoot movie footage at 4K/30p, while the Olympus is limited to 4K/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. The E-M5 III and the A7C are similar in the sense that both feature an electronic viewfinder, which is helpful when framing images in bright sunlight. Moreover, their viewfinders offer an identical resolution of 2360k dots. The table below summarizes some of the other core capabilities of the Olympus E-M5 III and Sony A7C in connection with corresponding information for a sample of similar cameras.

Core Features

		Camera Model	Viewfinder (Type or 000 dots)	Control Panel (yes/no)	LCD Size (inch)	LCD Resolution (000 dots)	LCD Attach- ment	Touch Screen (yes/no)	Mech Shutter Speed	Shutter Flaps (1/sec)	Built-in Flash (yes/no)	Built-in Image Stab
1.		Olympus E-M5 III	2360	n	3.0	1040	swivel	Y	1/8000s	10.0	n	Y
2.		Sony A7C	2360	n	3.0	922	swivel	Y	1/4000s	10.0	n	Y
3.		Olympus E-M1 III	2360	n	3.0	1037	swivel	Y	1/8000s	18.0	n	Y
4.		Olympus E-M10 IV	2360	n	3.0	1040	tilting	Y	1/4000s	15.0	Y	Y
5.		Olympus E-M1X	2360	n	3.0	1037	swivel	Y	1/8000s	18.0	n	Y
6.		Olympus E-M1 II	2360	n	3.0	1037	swivel	Y	1/8000s	18.0	n	Y
7.		Olympus PEN-F	2360	n	3.0	1037	swivel	Y	1/8000s	10.0	n	Y
8.		Olympus E-M5 II	2360	n	3.0	1037	swivel	Y	1/8000s	10.0	n	Y
9.		Olympus E-M1	2360	n	3.0	1037	tilting	Y	1/8000s	10.0	n	Y
10.		Olympus E-M5	1440	n	3.0	610	tilting	Y	1/4000s	9.0	n	Y
11.		Panasonic G90	2360	n	3.0	1240	swivel	Y	1/4000s	9.0	Y	Y
12.		Panasonic GX8	2360	n	3.0	1040	swivel	Y	1/8000s	10.0	n	Y
13.		Sony A6600	2359	n	3.0	922	tilting	Y	1/4000s	11.0	n	Y
14.		Sony A9	3686	n	3.0	1440	tilting	Y	1/8000s	20.0	n	Y
15.		Sony A6500	2359	n	3.0	922	tilting	Y	1/4000s	11.0	Y	Y
16.		Sony A7 II	2400	n	3.0	1230	tilting	n	1/8000s	5.0	n	Y
17.		Sony A7	2400	n	3.0	1230	tilting	n	1/8000s	5.0	n	n

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 Olympus E-M5 III and the Sony A7C 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 E-M5 III writes its imaging data to SDXC cards, while the A7C uses SDXC or Memory Stick PRO Duo cards. Both cameras support UHS-II cards, which provide for 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 Olympus OM-D E-M5 Mark III and Sony Alpha A7C 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 Microphone	Internal Speaker	Microphone Port	Headphone Port	HDMI Port	USB Port	WiFi Support	NFC Support	Bluetooth Support
1.		Olympus E-M5 III	Y	stereo	mono	Y	-	micro	2.0	Y	-	Y
2.		Sony A7C	Y	stereo	mono	Y	Y	micro	3.2	Y	Y	Y
3.		Olympus E-M1 III	Y	stereo	mono	Y	Y	micro	3.1	Y	-	Y
4.		Olympus E-M10 IV	Y	stereo	mono	-	-	micro	2.0	Y	-	Y
5.		Olympus E-M1X	Y	stereo	mono	Y	Y	micro	3.0	Y	-	Y
6.		Olympus E-M1 II	Y	stereo	mono	Y	Y	micro	3.0	Y	-	-
7.		Olympus PEN-F	Y	stereo	mono	-	-	micro	2.0	Y	-	-
8.		Olympus E-M5 II	Y	stereo	mono	Y	-	micro	2.0	Y	-	-
9.		Olympus E-M1	Y	stereo	mono	Y	-	micro	2.0	Y	-	-
10.		Olympus E-M5	Y	stereo	mono	-	-	mini	2.0	-	-	-
11.		Panasonic G90	Y	stereo	mono	Y	Y	micro	2.0	Y	-	Y
12.		Panasonic GX8	Y	stereo	mono	Y	-	micro	2.0	Y	Y	-
13.		Sony A6600	Y	stereo	mono	Y	Y	YES	2.0	Y	Y	Y
14.		Sony A9	Y	stereo	mono	Y	Y	micro	2.0	Y	Y	Y
15.		Sony A6500	Y	stereo	mono	Y	-	micro	2.0	Y	Y	-
16.		Sony A7 II	Y	stereo	mono	Y	Y	micro	2.0	Y	Y	-
17.		Sony A7	Y	stereo	mono	Y	Y	micro	2.0	Y	Y	-

It is notable that the A7C has a headphone jack, which makes it possible to attach external headphones and monitor the quality of sound during the recording process. The E-M5 III lacks such a headphone port.

Both the E-M5 III and the A7C are recent models that are part of the current product line-up. The E-M5 III replaced the earlier Olympus E-M5 II, while the A7C 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 Olympus and Sony websites.

Review summary

So what is the bottom line? Which of the two cameras – the Olympus E-M5 III or the Sony A7C – has the upper hand? Is one clearly better than the other? Below is a summary of the relative strengths of each of the two contestants.

Reasons to prefer the Olympus OM-D E-M5 Mark III:

• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• High quality composites: Can combine several shots after pixel-shifting its sensor.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.68x vs 0.59x).
• More detailed LCD: Has a higher resolution rear screen (1040k vs 922k dots).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Less heavy: Is lighter (by 95g or 19 percent) and hence easier to carry around.
• More affordable: Was introduced into a lower priced category (33 percent cheaper at launch).
• More heavily discounted: Has been on the market for longer (launched in October 2019).

Advantages of the Sony Alpha A7C:

• More detail: Has more megapixels (24 vs 20.2MP), which boosts linear resolution by 11%.
• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better image quality: Is equipped with a larger and more technologically advanced sensor.
• Richer colors: The sensor size advantage translates into images with better, more accurate colors.
• More dynamic range: Larger sensor captures a wider spectrum of light and dark details.
• Better low-light sensitivity: Larger sensor produces good images even in poorly lit environments.
• Better video: Provides higher movie framerates (4K/30p versus 4K/30p).
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• More compact: Is smaller (124x71mm vs 125x85mm) and will fit more readily into a bag.
• Longer lasting: Gets more shots (740 versus 310) out of a single battery charge.
• Faster data transfer: Supports a more advanced USB protocol (3.2 vs 2.0).
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More modern: Was introduced somewhat (10 months) more recently.

If the count of relative strengths (bullet points above) is taken as a measure, the A7C is the clear winner of the contest (13 : 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 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 Olympus E-M5 III and the Sony A7C 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 says little about, for example, the shooting experience and imaging performance of the E-M5 III and the A7C in practical situations. 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 table below provides a synthesis of the camera assessments of some of the best known photo-gear review sites (amateurphotographer [AP], cameralabs [CL], 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	DPR   score	EPZ   score	PB   score	Camera Launch	Launch Price (USD)	Street Price
1.		Olympus E-M5 III	5/5	+	82/100	4.5/5	4.5/5	Oct 2019	1,199
2.		Sony A7C	3.5/5	..	86/100	4/5	4/5	Sep 2020	1,799
3.		Olympus E-M1 III	5/5	..	83/100	4.5/5	4/5	Feb 2020	1,799
4.		Olympus E-M10 IV	4.5/5	..	..	4.5/5	4.5/5	Aug 2020	699
5.		Olympus E-M1X	4.5/5	o	..	4.5/5	..	Jan 2019	2,999
6.		Olympus E-M1 II	5/5	+ +	85/100	4.5/5	4.5/5	Sep 2016	1,999
7.		Olympus PEN-F	..	..	82/100	4.5/5	5/5	Jan 2016	1,199
8.		Olympus E-M5 II	5/5	+ +	81/100	5/5	5/5	Feb 2015	1,099
9.		Olympus E-M1	5/5	+ +	84/100	4.5/5	4.5/5	Sep 2013	1,399
10.		Olympus E-M5	4/5	+ +	80/100	4.5/5	5/5	Feb 2012	1,299
11.		Panasonic G90	4.5/5	+	83/100	4.5/5	4.5/5	Apr 2019	999
12.		Panasonic GX8	5/5	+	82/100	4.5/5	4.5/5	Jul 2015	1,199
13.		Sony A6600	4/5	+	83/100	4.5/5	4/5	Aug 2019	1,399
14.		Sony A9	5/5	+ +	89/100	5/5	5/5	Apr 2017	4,499
15.		Sony A6500	5/5	+ +	85/100	4.5/5	4.5/5	Oct 2016	1,399
16.		Sony A7 II	5/5	+	82/100	4.5/5	5/5	Nov 2014	1,999
17.		Sony A7	5/5	+ +	80/100	5/5	5/5	Oct 2013	1,699
Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. Also, please note that some of the review sites have changed their methodology and reporting over time.

Other camera comparisons

Did this review help to inform your camera decision process? In case you are interested in seeing how other cameras pair up, just make your choice using the following search menu. 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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Specifications: Olympus E-M5 III vs Sony A7C

Below is a side-by-side comparison of the specs of the two cameras to facilitate a quick review of their differences and common features.

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