Olympus E-M1 II vs Sony A7S III
The Olympus OM-D E-M1 Mark II and the Sony Alpha 7S III are two digital cameras that were revealed to the public, respectively, in September 2016 and July 2020. Both the E-M1 II and the A7S III are mirrorless interchangeable lens cameras that are based on a Four Thirds (E-M1 II) and a full frame (A7S III) sensor. The Olympus has a resolution of 20.2 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.
Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus OM-D E-M1 Mark II 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.
The physical size and weight of the Olympus E-M1 II 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 perspectives from the front, the top, and the back are available. All size dimensions are rounded to the nearest millimeter.
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 somewhat larger (1 percent) than the Olympus E-M1 II. Moreover, the A7S III is markedly heavier (22 percent) than the E-M1 II. 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-M1 II) 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-M1 II gets 440 shots out of its BLH-1 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 following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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.
|1.||Olympus E-M1 II||134 mm||91 mm||67 mm||574 g||440||Y||Sep 2016||1,999|
|2.||Sony A7S III||127 mm||97 mm||81 mm||699 g||600||Y||Jul 2020||3,499|
|3.||Olympus E-M1 III||134 mm||91 mm||69 mm||580 g||420||Y||Feb 2020||1,799|
|4.||Olympus PEN-F||125 mm||72 mm||37 mm||427 g||330||n||Jan 2016||1,199|
|5.||Olympus E-M5 II||124 mm||85 mm||45 mm||469 g||310||Y||Feb 2015||1,099|
|6.||Olympus E-M1||130 mm||94 mm||63 mm||497 g||350||Y||Sep 2013||1,399|
|7.||Panasonic G9||137 mm||97 mm||92 mm||658 g||400||Y||Nov 2017||1,699|
|8.||Panasonic GH5||139 mm||98 mm||87 mm||725 g||410||Y||Jan 2017||1,999|
|9.||Panasonic G85||128 mm||89 mm||74 mm||505 g||330||Y||Sep 2016||899|
|10.||Panasonic GX8||133 mm||78 mm||63 mm||487 g||330||Y||Jul 2015||1,199|
|11.||Sony A7R IV||129 mm||96 mm||78 mm||665 g||670||Y||Jul 2019||3,499|
|12.||Sony A7R III||127 mm||96 mm||74 mm||650 g||650||Y||Oct 2017||3,199|
|13.||Sony A9||127 mm||96 mm||63 mm||673 g||650||Y||Apr 2017||4,499|
|14.||Sony A7R II||127 mm||96 mm||60 mm||625 g||290||Y||Jun 2015||3,199|
|15.||Sony A7S II||127 mm||96 mm||60 mm||627 g||370||Y||Sep 2015||2,999|
|16.||Sony A7 II||127 mm||96 mm||60 mm||599 g||350||Y||Nov 2014||1,999|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
Any camera decision will obviously take relative prices into account. 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 E-M1 II was launched at a markedly lower price (by 43 percent) than the A7S III, 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.
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. 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.
Of the two cameras under consideration, the Olympus E-M1 II 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-M1 II 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-M1 II offers a higher resolution of 20.2 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 3.34μm versus 8.40μm for the A7S III). Moreover, it should be noted that the A7S III is much more recent (by 3 years and 10 months) than the E-M1 II, 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-M1 II has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.
The resolution advantage of the Olympus E-M1 II implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the E-M1 II for good quality output (200 dots per inch) amounts to 25.9 x 19.4 inches or 65.8 x 49.4 cm, for very good quality (250 dpi) 20.7 x 15.6 inches or 52.7 x 39.5 cm, and for excellent quality (300 dpi) 17.3 x 13 inches or 43.9 x 32.9 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 E-M1 II has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.
Unlike the A7S III, the E-M1 II has the capacity to capture high quality composite images (50MP) 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-M1 Mark II 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 7S III are ISO 80 to ISO 102400, with the possibility to increase the ISO range to 40-409600.
Consistent information on actual sensor performance is available from DXO Mark for many cameras. 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 consideration, the A7S III has a markedly higher DXO score than the E-M1 II (overall score 6 points higher), which will translate into better image quality. 1.1 EV in additional dynamic range, and 0.9 stops in additional low light sensitivity. The table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar cameras.
| DXO |
|1.||Olympus E-M1 II||Four Thirds||20.2||5184||3888||4K/30p||23.7||12.8||1312||80|
|2.||Sony A7S III||Full Frame||12.0||4240||2832||4K/120p||23.7||13.9||2520||86|
|3.||Olympus E-M1 III||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|4.||Olympus PEN-F||Four Thirds||20.2||5184||3888||1080/60p||23.1||12.4||894||74|
|5.||Olympus E-M5 II||Four Thirds||15.9||4608||3456||1080/60p||23.0||12.5||842||73|
|6.||Olympus E-M1||Four Thirds||15.9||4608||3456||1080/30p||23.0||12.7||757||73|
|7.||Panasonic G9||Four Thirds||20.2||5184||3888||4K/60p||..||..||..||..|
|8.||Panasonic GH5||Four Thirds||20.2||5184||3888||4K/60p||23.9||13.0||807||77|
|9.||Panasonic G85||Four Thirds||15.8||4592||3448||4K/30p||22.8||12.5||656||71|
|10.||Panasonic GX8||Four Thirds||20.2||5184||3888||4K/30p||23.5||12.6||806||75|
|11.||Sony A7R IV||Full Frame||60.2||9504||6336||4K/30p||26.0||14.8||3344||99|
|12.||Sony A7R III||Full Frame||42.2||7952||5304||4K/30p||26.0||14.7||3523||100|
|13.||Sony A9||Full Frame||24.0||6000||4000||4K/30p||24.9||13.3||3517||92|
|14.||Sony A7R II||Full Frame||42.2||7952||5304||4K/30p||26.0||13.9||3434||98|
|15.||Sony A7S II||Full Frame||12.0||4240||2832||4K/30p||23.6||13.3||2993||85|
|16.||Sony A7 II||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
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 A7S III provides a faster frame rate than the E-M1 II. It can shoot movie footage at 4K/120p, while the Olympus is limited to 4K/30p.
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-M1 II (9440k vs 2360k dots). The table below summarizes some of the other core capabilities of the Olympus E-M1 II and Sony A7S III in connection with corresponding information for a sample of similar cameras.
|1.||Olympus E-M1 II||2360||n||3.0||1037||swivel||Y||1/8000s||18.0||n||Y|
|2.||Sony A7S III||9440||n||3.0||1440||swivel||Y||1/8000s||10.0||n||Y|
|3.||Olympus E-M1 III||2360||n||3.0||1037||swivel||Y||1/8000s||18.0||n||Y|
|5.||Olympus E-M5 II||2360||n||3.0||1037||swivel||Y||1/8000s||10.0||n||Y|
|11.||Sony A7R IV||5760||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|12.||Sony A7R III||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|14.||Sony A7R II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
|15.||Sony A7S II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
|16.||Sony A7 II||2400||n||3.0||1230||tilting||n||1/8000s||5.0||n||Y|
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-M1 II 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-M1 II writes its imaging data to SDXC cards, while the A7S III uses CFexpress or SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. However, while the A7S III supports UHS-II cards (Ultra High Speed data transfer of up to 312 MB/s) on both slots, the E-M1 II supports UHS-II only on its first slot and UHS-I (data transfer speed up to 104 MB/s) on the second one.
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-M1 Mark II and Sony Alpha 7S III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|1.||Olympus E-M1 II||Y||stereo||mono||Y||Y||micro||3.0||Y||-||-|
|2.||Sony A7S III||Y||stereo||mono||Y||Y||full||3.2||Y||-||Y|
|3.||Olympus E-M1 III||Y||stereo||mono||Y||Y||micro||3.1||Y||-||Y|
|5.||Olympus E-M5 II||Y||stereo||mono||Y||-||micro||2.0||Y||-||-|
|11.||Sony A7R IV||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|12.||Sony A7R III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|14.||Sony A7R II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|15.||Sony A7S II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|16.||Sony A7 II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
Studio photographers will appreciate that the Olympus E-M1 II (unlike the A7S III) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Both the E-M1 II and the A7S III are recent models that are part of the current product line-up. The E-M1 II replaced the earlier Olympus E-M1, while the A7S III followed on from the Sony A7S II. 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.
So how do things add up? Is the Olympus E-M1 II better than the Sony A7S III or vice versa? Below is a summary of the relative strengths of each of the two contestants.
Reasons to prefer the Olympus OM-D E-M1 Mark II:
- More detail: Offers more megapixels (20.2 vs 12MP) with a 27% higher linear resolution.
- 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.
- Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
- Faster burst: Shoots at higher frequency (18 vs 10 flaps/sec) to capture the decisive moment.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- Less heavy: Is lighter (by 125g or 18 percent) and hence easier to carry around.
- Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
- More affordable: Was introduced into a lower priced category (43 percent cheaper at launch).
- More heavily discounted: Has been available for much longer (launched in September 2016).
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: Scores markedly higher (6 points) in the DXO overall evaluation.
- More dynamic range: Captures a broader range of light and dark details (1.1 EV of extra DR).
- Better low-light sensitivity: Can shoot in dim conditions (0.9 stops ISO advantage).
- Better video: Provides higher movie framerates (4K/120p versus 4K/30p).
- 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 0.74x).
- More detailed LCD: Has a higher resolution rear screen (1440k vs 1037k dots).
- Longer lasting: Gets more shots (600 versus 440) out of a single battery charge.
- Easier travel charging: Can be conveniently charged via its USB port.
- 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.
- More modern: Reflects 3 years and 10 months of technical progress since the E-M1 II launch.
If the count of individual advantages (bullet points above) is taken as a guide, the A7S III emerges as the winner of the match-up (13 : 10 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 sports photographer will view the differences between cameras in a way that diverges from the perspective of a street photog, and a person interested in family portraits has distinct needs from a landscape 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-M1 II 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 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 E-M1 II or the A7S III perform in practice. User reviews, such as those found at amazon, can sometimes inform about these issues, but such feedback is often incomplete, inconsistent, and biased.
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.
|1.||Olympus E-M1 II||5/5||+ +||85/100||4.5/5||4.5/5||Sep 2016||1,999|
|2.||Sony A7S III||..||+ +||91/100||4.5/5||5/5||Jul 2020||3,499|
|3.||Olympus E-M1 III||5/5||..||83/100||4.5/5||4/5||Feb 2020||1,799|
|4.||Olympus PEN-F||..||..||82/100||4.5/5||5/5||Jan 2016||1,199|
|5.||Olympus E-M5 II||5/5||+ +||81/100||5/5||5/5||Feb 2015||1,099|
|6.||Olympus E-M1||5/5||+ +||84/100||4.5/5||4.5/5||Sep 2013||1,399|
|7.||Panasonic G9||..||+ +||85/100||5/5||5/5||Nov 2017||1,699|
|8.||Panasonic GH5||4.5/5||+ +||85/100||4.5/5||5/5||Jan 2017||1,999|
|9.||Panasonic G85||..||+ +||84/100||5/5||4.5/5||Sep 2016||899|
|10.||Panasonic GX8||5/5||+||82/100||4.5/5||4.5/5||Jul 2015||1,199|
|11.||Sony A7R IV||5/5||+||91/100||4.5/5||5/5||Jul 2019||3,499|
|12.||Sony A7R III||..||+ +||90/100||4.5/5||5/5||Oct 2017||3,199|
|13.||Sony A9||5/5||+ +||89/100||5/5||5/5||Apr 2017||4,499|
|14.||Sony A7R II||5/5||+ +||90/100||5/5||5/5||Jun 2015||3,199|
|15.||Sony A7S II||5/5||+||..||4.5/5||5/5||Sep 2015||2,999|
|16.||Sony A7 II||5/5||+||82/100||4.5/5||5/5||Nov 2014||1,999|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
The above review scores should be interpreted with care, 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 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.
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. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.
Specifications: Olympus E-M1 II 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.
|Camera Model||Olympus E-M1 II||Sony A7S III|
|Camera Type||Mirrorless system camera||Mirrorless system camera|
|Camera Lens||Micro Four Thirds lenses||Sony E mount lenses|
|Launch Date||September 2016||July 2020|
|Launch Price||USD 1,999||USD 3,499|
|Sensor Specs||Olympus E-M1 II||Sony A7S III|
|Sensor Format||Four Thirds Sensor||Full Frame Sensor|
|Sensor Size||17.3 x 13.0 mm||35.6 x 23.8 mm|
|Sensor Area||224.9 mm2||847.28 mm2|
|Sensor Diagonal||21.6 mm||42.8 mm|
|Sensor Resolution||20.2 Megapixels||12 Megapixels|
|Image Resolution||5184 x 3888 pixels||4240 x 2832 pixels|
|Pixel Pitch||3.34 μm||8.40 μm|
|Pixel Density||8.96 MP/cm2||1.42 MP/cm2|
|Moiré control||no AA filter||Anti-Alias filter|
|Movie Capability||4K/30p Video||4K/120p Video|
|ISO Setting||200 - 25,600 ISO||80 - 102,400 ISO|
|ISO Boost||64 - 25,600 ISO||40 - 409,600 ISO|
|Image Processor||TruePic VIII||BIONZ XR|
|DXO Sensor Quality (score)||80||86|
|DXO Color Depth (bits)||23.7||23.7|
|DXO Dynamic Range (EV)||12.8||13.9|
|DXO Low Light (ISO)||1312||2520|
|Screen Specs||Olympus E-M1 II||Sony A7S III|
|Viewfinder Type||Electronic viewfinder||Electronic viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||2360k dots||9440k dots|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||1037k dots||1440k dots|
|LCD Attachment||Swivel screen||Swivel screen|
|Shooting Specs||Olympus E-M1 II||Sony A7S III|
|Focus System||On-Sensor Phase-detect||Contrast-detect AF|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/8000s||1/8000s|
|Continuous Shooting||18 shutter flaps/s||10 shutter flaps/s|
|Shutter Life Expectancy||200 000 actuations||200 000 actuations|
|Electronic Shutter||up to 1/32000s||YES|
|Time-Lapse Photography||Intervalometer built-in||no Intervalometer|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||no On-Board Flash||no On-Board Flash|
|Storage Medium||SDXC cards||CFexpress or SDXC cards|
|Second Storage Option||Dual card slots||Dual card slots|
|UHS card support||Single UHS-II||Dual UHS-II|
|Connectivity Specs||Olympus E-M1 II||Sony A7S III|
|Studio Flash||PC Sync socket||no PC Sync|
|USB Connector||USB 3.0||USB 3.2|
|HDMI Port||micro HDMI||full HDMI|
|Microphone Port||External MIC port||External MIC port|
|Headphone Socket||Headphone port||Headphone port|
|Wifi Support||Wifi built-in||Wifi built-in|
|Bluetooth Support||no Bluetooth||Bluetooth built-in|
|Body Specs||Olympus E-M1 II||Sony A7S III|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||440 shots per charge||600 shots per charge|
|In-Camera Charging||no USB charging||USB charging|
134 x 91 x 67 mm
(5.3 x 3.6 x 2.6 in)
127 x 97 x 81 mm
(5.0 x 3.8 x 3.2 in)
|Camera Weight||574 g (20.2 oz)||699 g (24.7 oz)|
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