Olympus E-M10 III vs Sony A7S III

The Olympus OM-D E-M10 Mark III and the Sony Alpha 7S III are two digital cameras that were revealed to the public, respectively, in August 2017 and July 2020. Both the E-M10 III and the A7S III are mirrorless interchangeable lens cameras that are based on a Four Thirds (E-M10 III) and a full frame (A7S III) sensor. The Olympus has a resolution of 15.9 megapixels, whereas the Sony provides 12 MP.

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

Headline Specifications

Olympus E-M10 III		Sony A7S III
Mirrorless system camera		Mirrorless system camera
Micro Four Thirds lenses		Sony E mount lenses
15.9 MP, Four Thirds Sensor		12 MP, Full Frame Sensor
4K/30p Video		4K/120p Video
ISO 200-25,600		ISO 80-102,400 (40 - 409,600)
Electronic viewfinder (2360k dots)		Electronic viewfinder (9440k dots)
3.0 LCD, 1040k dots		3.0 LCD, 1440k dots
Tilting touchscreen		Swivel touchscreen
8.6 shutter flaps per second		10 shutter flaps per second
In-body stabilization		In-body stabilization
not weather sealed		Weathersealed body
330 shots per battery charge		600 shots per battery charge
122 x 84 x 50 mm, 410 g		127 x 97 x 81 mm, 699 g

Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus OM-D E-M10 Mark III and the Sony Alpha 7S III? 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 Olympus E-M10 III and the Sony A7S III are illustrated 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 size dimensions are rounded to the nearest millimeter.

The E-M10 III can be obtained in two different colors (black, silver), while the A7S III 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 Sony A7S III is notably larger (20 percent) than the Olympus E-M10 III. Moreover, the A7S III is substantially heavier (70 percent) than the E-M10 III. It is noteworthy in this context that the A7S III is splash and dust-proof, while the E-M10 III 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. 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-M10 III) and the Sony FE Lens Catalog (A7S III). 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-M10 III gets 330 shots out of its BLS-50 battery, while the A7S III can take 600 images on a single charge of its NP-FZ100 power pack. The power pack in the A7S III can be charged via the USB port, 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 want to switch the focus of the display and review another camera pair, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons 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-M10 III	122 mm	84 mm	50 mm	410 g	330	n	Aug 2017	649
2.		Sony A7S III	127 mm	97 mm	81 mm	699 g	600	Y	Jul 2020	3,499
3.		Olympus E-M10 IV	122 mm	84 mm	49 mm	383 g	360	n	Aug 2020	699
4.		Olympus E-PL10	117 mm	68 mm	39 mm	380 g	350	n	Oct 2019	599
5.		Olympus E-PL9	117 mm	68 mm	39 mm	380 g	350	n	Feb 2018	599
6.		Olympus E-PL8	115 mm	67 mm	38 mm	357 g	350	n	Sep 2016	549
7.		Olympus PEN-F	125 mm	72 mm	37 mm	427 g	330	n	Jan 2016	1,199
8.		Olympus E-M10 II	120 mm	83 mm	47 mm	390 g	320	n	Aug 2015	649
9.		Olympus E-M10	119 mm	82 mm	46 mm	396 g	320	n	Jan 2014	699
10.		Olympus E-PL7	115 mm	67 mm	38 mm	357 g	350	n	Aug 2014	599
11.		Olympus E-P5	122 mm	69 mm	37 mm	420 g	330	n	May 2013	999
12.		Panasonic GX80	122 mm	71 mm	44 mm	426 g	290	n	Apr 2016	799
13.		Sony A7R IV	129 mm	96 mm	78 mm	665 g	670	Y	Jul 2019	3,499
14.		Sony A7R III	127 mm	96 mm	74 mm	650 g	650	Y	Oct 2017	3,199
15.		Sony A9	127 mm	96 mm	63 mm	673 g	650	Y	Apr 2017	4,499
16.		Sony A7R II	127 mm	96 mm	60 mm	625 g	290	Y	Jun 2015	3,199
17.		Sony A7S II	127 mm	96 mm	60 mm	627 g	370	Y	Sep 2015	2,999
Notes: 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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The E-M10 III was launched at a markedly lower price (by 81 percent) than the A7S III, 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 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. 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 more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Olympus E-M10 III features a Four Thirds sensor and the Sony A7S III a full frame sensor. The sensor area in the A7S III 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-M10 III has a native 4:3 aspect ratio, while the one in the A7S III offers a 3:2 aspect.

Despite having a smaller sensor, the Olympus E-M10 III offers a higher resolution of 15.9 megapixels, compared with 12 MP of the Sony A7S III. 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 3.76μm versus 8.40μm for the A7S III). Moreover, it should be noted that the A7S III is much more recent (by 2 years and 10 months) than the E-M10 III, and its sensor will 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-M10 III has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Olympus E-M10 III implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the E-M10 III for good quality output (200 dots per inch) amounts to 23 x 17.3 inches or 58.5 x 43.9 cm, for very good quality (250 dpi) 18.4 x 13.8 inches or 46.8 x 35.1 cm, and for excellent quality (300 dpi) 15.4 x 11.5 inches or 39 x 29.3 cm. The corresponding values for the Sony A7S III are 21.2 x 14.2 inches or 53.8 x 36 cm for good quality, 17 x 11.3 inches or 43.1 x 28.8 cm for very good quality, and 14.1 x 9.4 inches or 35.9 x 24 cm for excellent quality prints.

The Olympus OM-D E-M10 Mark III has a native sensitivity range from ISO 200 to ISO 25600, which can be extended to ISO 100-25600. The corresponding ISO settings for the Sony Alpha 7S III are ISO 80 to ISO 102400, with the possibility to increase the ISO range to 40-409600.

Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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"). 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-M10 III	Four Thirds	15.9	4608	3456	4K/30p	..	..	..	..
2.		Sony A7S III	Full Frame	12.0	4240	2832	4K/120p	23.7	13.9	2520	86
3.		Olympus E-M10 IV	Four Thirds	20.2	5184	3888	4K/30p	..	..	..	..
4.		Olympus E-PL10	Four Thirds	15.9	4608	3456	4K/30p	..	..	..	..
5.		Olympus E-PL9	Four Thirds	15.9	4608	3456	4K/30p	..	..	..	..
6.		Olympus E-PL8	Four Thirds	15.9	4608	3456	1080/30p	..	..	..	..
7.		Olympus PEN-F	Four Thirds	20.2	5184	3888	1080/60p	23.1	12.4	894	74
8.		Olympus E-M10 II	Four Thirds	15.9	4608	3456	1080/60p	23.1	12.5	842	73
9.		Olympus E-M10	Four Thirds	15.9	4608	3456	1080/30p	22.8	12.3	884	72
10.		Olympus E-PL7	Four Thirds	15.9	4608	3456	1080/30p	22.7	12.4	873	72
11.		Olympus E-P5	Four Thirds	15.9	4608	3456	1080/30p	22.8	12.4	895	72
12.		Panasonic GX80	Four Thirds	15.8	4592	3448	4K/30p	22.9	12.6	662	71
13.		Sony A7R IV	Full Frame	60.2	9504	6336	4K/30p	26.0	14.8	3344	99
14.		Sony A7R III	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
15.		Sony A9	Full Frame	24.0	6000	4000	4K/30p	24.9	13.3	3517	92
16.		Sony A7R II	Full Frame	42.2	7952	5304	4K/30p	26.0	13.9	3434	98
17.		Sony A7S II	Full Frame	12.0	4240	2832	4K/30p	23.6	13.3	2993	85

Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the A7S III provides a faster frame rate than the E-M10 III. It can shoot movie footage at 4K/120p, while the Olympus is limited to 4K/30p.

Feature comparison

Beyond body and sensor, cameras can and do differ across a range of features. The two cameras under review are similar with respect to both having an electronic viewfinder. However, the one in the A7S III offers a substantially higher resolution than the one in the E-M10 III (9440k vs 2360k dots). The adjacent table lists some of the other core features of the Olympus E-M10 III and Sony A7S III along with similar information for a selection of comparators.

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-M10 III	2360	n	3.0	1040	tilting	Y	1/4000s	8.6	Y	Y
2.		Sony A7S III	9440	n	3.0	1440	swivel	Y	1/8000s	10.0	n	Y
3.		Olympus E-M10 IV	2360	n	3.0	1040	tilting	Y	1/4000s	15.0	Y	Y
4.		Olympus E-PL10	none	n	3.0	1040	tilting	Y	1/4000s	8.6	Y	Y
5.		Olympus E-PL9	none	n	3.0	1040	tilting	Y	1/4000s	8.6	Y	Y
6.		Olympus E-PL8	optional	n	3.0	1037	tilting	Y	1/4000s	8.0	n	Y
7.		Olympus PEN-F	2360	n	3.0	1037	swivel	Y	1/8000s	10.0	n	Y
8.		Olympus E-M10 II	2360	n	3.0	1040	tilting	Y	1/4000s	8.0	Y	Y
9.		Olympus E-M10	1440	n	3.0	1037	tilting	Y	1/4000s	8.0	Y	Y
10.		Olympus E-PL7	optional	n	3.0	1037	tilting	Y	1/4000s	8.0	n	Y
11.		Olympus E-P5	optional	n	3.0	1037	tilting	Y	1/8000s	9.0	Y	Y
12.		Panasonic GX80	2765	n	3.0	1040	tilting	Y	1/4000s	8.0	Y	Y
13.		Sony A7R IV	5760	n	3.0	1440	tilting	Y	1/8000s	10.0	n	Y
14.		Sony A7R III	3686	n	3.0	1440	tilting	Y	1/8000s	10.0	n	Y
15.		Sony A9	3686	n	3.0	1440	tilting	Y	1/8000s	20.0	n	Y
16.		Sony A7R II	2400	n	3.0	1229	tilting	n	1/8000s	5.0	n	Y
17.		Sony A7S II	2400	n	3.0	1229	tilting	n	1/8000s	5.0	n	Y

One difference between the cameras concerns the presence of an on-board flash. The E-M10 III has one, while the A7S III does not. While the built-in flash of the E-M10 III is not very powerful, it can at times be useful as a fill-in light.

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-M10 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.

The E-M10 III writes its imaging data to SDXC cards, while the A7S III uses CFexpress or SDXC cards. The A7S III features dual card slots, which can be very useful in case a memory card fails. In contrast, the E-M10 III only has one slot. Moreover, both cameras support UHS-II cards (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-M10 Mark III and Sony Alpha 7S III 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-M10 III	Y	stereo	mono	-	-	micro	2.0	Y	-	-
2.		Sony A7S III	Y	stereo	mono	Y	Y	full	3.2	Y	-	Y
3.		Olympus E-M10 IV	Y	stereo	mono	-	-	micro	2.0	Y	-	Y
4.		Olympus E-PL10	Y	stereo	mono	-	-	micro	2.0	Y	-	Y
5.		Olympus E-PL9	Y	stereo	mono	-	-	micro	2.0	Y	-	Y
6.		Olympus E-PL8	Y	stereo	mono	-	-	micro	2.0	Y	-	-
7.		Olympus PEN-F	Y	stereo	mono	-	-	micro	2.0	Y	-	-
8.		Olympus E-M10 II	Y	stereo	mono	-	-	micro	2.0	Y	-	-
9.		Olympus E-M10	Y	stereo	mono	-	-	micro	2.0	Y	-	-
10.		Olympus E-PL7	Y	stereo	mono	-	-	micro	2.0	Y	-	-
11.		Olympus E-P5	Y	stereo	mono	-	-	micro	2.0	Y	-	-
12.		Panasonic GX80	Y	stereo	mono	-	-	micro	2.0	Y	-	-
13.		Sony A7R IV	Y	stereo	mono	Y	Y	micro	3.1	Y	Y	Y
14.		Sony A7R III	Y	stereo	mono	Y	Y	micro	3.1	Y	Y	Y
15.		Sony A9	Y	stereo	mono	Y	Y	micro	2.0	Y	Y	Y
16.		Sony A7R II	Y	stereo	mono	Y	Y	micro	2.0	Y	Y	-
17.		Sony A7S II	Y	stereo	mono	Y	Y	micro	2.0	Y	Y	-

It is notable that the A7S III has a headphone jack, which makes it possible to attach external headphones and monitor the quality of sound during the recording process. The E-M10 III lacks such a headphone port.

The A7S III is a recent model that features in the current product line-up of Sony. In contrast, the E-M10 III has been discontinued (but can be found pre-owned on eBay). As a replacement in the same line of cameras, the E-M10 III was succeeded by the Olympus E-M10 IV. 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 conclusions can be drawn? Is there a clear favorite between the Olympus E-M10 III and the Sony A7S III? Which camera is better? The listing below highlights the relative strengths of the two models.

Arguments in favor of the Olympus OM-D E-M10 Mark III:

• More detail: Offers more megapixels (15.9 vs 12MP) with a 13% higher linear resolution.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• More compact: Is smaller (122x84mm vs 127x97mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 289g or 41 percent) and hence easier to carry around.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• More affordable: Was introduced into a lower priced category (81 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in August 2017).

Advantages of the Sony Alpha 7S III:

• 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/120p versus 4K/30p).
• 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.
• More detailed viewfinder: Has higher resolution electronic viewfinder (9440k vs 2360k dots).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.91x vs 0.62x).
• More detailed LCD: Has a higher resolution rear screen (1440k vs 1040k dots).
• 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 (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (10 vs 8.6 flaps/sec) to capture the decisive moment.
• Longer lasting: Gets more shots (600 versus 330) out of a single battery charge.
• Easier travel charging: Can be conveniently charged via its USB port.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Faster data transfer: Supports a more advanced USB protocol (3.2 vs 2.0).
• More solid recording: Has a full-sized HDMI port for a sturdy connection to an external recorder.
• Easier wireless transfer: Supports Bluetooth for image sharing without cables.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• More modern: Reflects 2 years and 10 months of technical progress since the E-M10 III launch.

If the count of relative strengths (bullet points above) is taken as a measure, the A7S III is the clear winner of the contest (23 : 8 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 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-M10 III and the Sony A7S III 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 specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it says little about, for example, the shooting experience and imaging performance of the E-M10 III and the A7S III in practical situations. 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 adjacent summary-table relays the overall verdicts of several of the most popular camera 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-M10 III	..	+	80/100	4.5/5	4.5/5	Aug 2017	649
2.		Sony A7S III	..	+ +	91/100	4.5/5	5/5	Jul 2020	3,499
3.		Olympus E-M10 IV	4.5/5	..	..	4.5/5	4.5/5	Aug 2020	699
4.		Olympus E-PL10	..	..	77/100	..	4/5	Oct 2019	599
5.		Olympus E-PL9	..	+	..	4.5/5	4/5	Feb 2018	599
6.		Olympus E-PL8	..	..	..	4.5/5	4/5	Sep 2016	549
7.		Olympus PEN-F	..	..	82/100	4.5/5	5/5	Jan 2016	1,199
8.		Olympus E-M10 II	4.5/5	+ +	80/100	5/5	5/5	Aug 2015	649
9.		Olympus E-M10	4/5	..	80/100	5/5	5/5	Jan 2014	699
10.		Olympus E-PL7	4/5	+	..	5/5	4/5	Aug 2014	599
11.		Olympus E-P5	5/5	+ +	78/100	4.5/5	5/5	May 2013	999
12.		Panasonic GX80	4.5/5	+ +	82/100	5/5	5/5	Apr 2016	799
13.		Sony A7R IV	5/5	+	91/100	4.5/5	5/5	Jul 2019	3,499
14.		Sony A7R III	..	+ +	90/100	4.5/5	5/5	Oct 2017	3,199
15.		Sony A9	5/5	+ +	89/100	5/5	5/5	Apr 2017	4,499
16.		Sony A7R II	5/5	+ +	90/100	5/5	5/5	Jun 2015	3,199
17.		Sony A7S II	5/5	+	..	4.5/5	5/5	Sep 2015	2,999
Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, though. The ratings are only valid when referring to cameras in the same category and of the same age. Thus, a score needs to be put into the context of the launch date and the launch price 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. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

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 use the search menu 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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Specifications: Olympus E-M10 III vs Sony A7S III

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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