Olympus E-M5 III vs Sony A7S III
The Olympus OM-D E-M5 Mark III and the Sony Alpha 7S III are two digital cameras that were announced, respectively, in October 2019 and July 2020. Both the E-M5 III and the A7S III are mirrorless interchangeable lens cameras that are based on a Four Thirds (E-M5 III) 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-M5 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.
The side-by-side display below illustrates the physical size and weight of the Olympus E-M5 III and the Sony A7S III. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All width, height and depth measures are rounded to the nearest millimeter.
The E-M5 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 (16 percent) than the Olympus E-M5 III. Moreover, the A7S III is substantially heavier (69 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 (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-M5 III gets 310 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 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 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.
|1.||Olympus E-M5 III||125 mm||85 mm||50 mm||414 g||310||Y||Oct 2019||1,199|
|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 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 PEN-F||125 mm||72 mm||37 mm||427 g||330||n||Jan 2016||1,199|
|7.||Olympus E-M5 II||124 mm||85 mm||45 mm||469 g||310||Y||Feb 2015||1,099|
|8.||Olympus E-M1||130 mm||94 mm||63 mm||497 g||350||Y||Sep 2013||1,399|
|9.||Olympus E-M5||122 mm||89 mm||43 mm||425 g||360||Y||Feb 2012||1,299|
|10.||Panasonic G90||130 mm||94 mm||77 mm||536 g||290||Y||Apr 2019||999|
|11.||Panasonic GX8||133 mm||78 mm||63 mm||487 g||330||Y||Jul 2015||1,199|
|12.||Sony A7R IV||129 mm||96 mm||78 mm||665 g||670||Y||Jul 2019||3,499|
|13.||Sony A6600||120 mm||67 mm||69 mm||503 g||810||Y||Aug 2019||1,399|
|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.|
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-M5 III was launched at a markedly lower price (by 66 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.
The size of the imaging sensor is a crucial determinant of image quality. A large sensor will tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixel-units 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 associated with larger, more expensive camera bodies and lenses.
Of the two cameras under consideration, the Olympus E-M5 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-M5 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-M5 III 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 a somewhat more recent model (by 9 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 Olympus E-M5 III implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the E-M5 III 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-M5 III 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-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 7S III are ISO 80 to ISO 102400, with the possibility to increase the ISO range to 40-409600.
For many cameras, data on sensor performance has been reported by DXO Mark. 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 adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.
| DXO |
|1.||Olympus E-M5 III||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|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 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 PEN-F||Four Thirds||20.2||5184||3888||1080/60p||23.1||12.4||894||74|
|7.||Olympus E-M5 II||Four Thirds||15.9||4608||3456||1080/60p||23.0||12.5||842||73|
|8.||Olympus E-M1||Four Thirds||15.9||4608||3456||1080/30p||23.0||12.7||757||73|
|9.||Olympus E-M5||Four Thirds||15.9||4608||3456||1080/60i||22.8||12.3||826||71|
|10.||Panasonic G90||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|11.||Panasonic GX8||Four Thirds||20.2||5184||3888||4K/30p||23.5||12.6||806||75|
|12.||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-M5 III. It can shoot movie footage at 4K/120p, while the Olympus is limited to 4K/30p.
Apart from 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-M5 III (9440k vs 2360k dots). The following table reports on some other key feature differences and similarities of the Olympus E-M5 III, the Sony A7S III, and comparable cameras.
|1.||Olympus E-M5 III||2360||n||3.0||1040||swivel||Y||1/8000s||10.0||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|
|4.||Olympus E-M10 IV||2360||n||3.0||1040||tilting||Y||1/4000s||15.0||Y||Y|
|7.||Olympus E-M5 II||2360||n||3.0||1037||swivel||Y||1/8000s||10.0||n||Y|
|12.||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|
|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|
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 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-M5 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-M5 III only has one slot. Moreover, both cameras support UHS-II cards (Ultra High Speed data transfer of up to 312 MB/s).
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 7S III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|1.||Olympus E-M5 III||Y||stereo||mono||Y||-||micro||2.0||Y||-||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|
|4.||Olympus E-M10 IV||Y||stereo||mono||-||-||micro||2.0||Y||-||Y|
|7.||Olympus E-M5 II||Y||stereo||mono||Y||-||micro||2.0||Y||-||-|
|12.||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|
|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-M5 III lacks such a headphone port.
Both the E-M5 III and the A7S III 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 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? Which of the two cameras – the Olympus E-M5 III or the Sony A7S III – has the upper hand? Is one clearly better than the other? A synthesis of the relative strong points of each of the models is listed below.
Reasons to prefer the Olympus OM-D E-M5 Mark III:
- 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.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- More compact: Is smaller (125x85mm vs 127x97mm) and thus needs less room in the bag.
- Less heavy: Is lighter (by 285g or 41 percent) and hence easier to carry around.
- More affordable: Was introduced into a lower priced category (66 percent cheaper at launch).
- More heavily discounted: Has been on the market for longer (launched in October 2019).
Arguments in favor 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 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 0.68x).
- More detailed LCD: Has a higher resolution rear screen (1440k vs 1040k dots).
- Longer lasting: Gets more shots (600 versus 310) out of a single battery charge.
- 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.
- Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
- More modern: Was introduced somewhat (9 months) more recently.
If the number of relative strengths (bullet points above) is taken as a guide, the A7S III is the clear winner of the contest (15 : 9 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-M5 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 comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it remains incomplete and does no justice, for example, to the way the E-M5 III 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 where reviews by experts come in. 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-M5 III||5/5||+||82/100||4.5/5||4.5/5||Oct 2019||1,199|
|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 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 PEN-F||..||..||82/100||4.5/5||5/5||Jan 2016||1,199|
|7.||Olympus E-M5 II||5/5||+ +||81/100||5/5||5/5||Feb 2015||1,099|
|8.||Olympus E-M1||5/5||+ +||84/100||4.5/5||4.5/5||Sep 2013||1,399|
|9.||Olympus E-M5||4/5||+ +||80/100||4.5/5||5/5||Feb 2012||1,299|
|10.||Panasonic G90||4.5/5||+||83/100||4.5/5||4.5/5||Apr 2019||999|
|11.||Panasonic GX8||5/5||+||82/100||4.5/5||4.5/5||Jul 2015||1,199|
|12.||Sony A7R IV||5/5||+||91/100||4.5/5||5/5||Jul 2019||3,499|
|13.||Sony A6600||4/5||+||83/100||4.5/5||4/5||Aug 2019||1,399|
|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 above review scores should be interpreted with care, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparisons of ratings among very different cameras or across long time periods 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? In case you are interested in seeing how other cameras pair up, just make a corresponding selection in the search boxes below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.
Specifications: Olympus E-M5 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.
|Camera Model||Olympus E-M5 III||Sony A7S III|
|Camera Type||Mirrorless system camera||Mirrorless system camera|
|Camera Lens||Micro Four Thirds lenses||Sony E mount lenses|
|Launch Date||October 2019||July 2020|
|Launch Price||USD 1,199||USD 3,499|
|Sensor Specs||Olympus E-M5 III||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)||..||86|
|DXO Color Depth (bits)||..||23.7|
|DXO Dynamic Range (EV)||..||13.9|
|DXO Low Light (ISO)||..||2520|
|Screen Specs||Olympus E-M5 III||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||1040k dots||1440k dots|
|LCD Attachment||Swivel screen||Swivel screen|
|Shooting Specs||Olympus E-M5 III||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||10 shutter flaps/s||10 shutter flaps/s|
|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||Single card slot||Dual card slots|
|UHS card support||UHS-II||Dual UHS-II|
|Connectivity Specs||Olympus E-M5 III||Sony A7S III|
|USB Connector||USB 2.0||USB 3.2|
|HDMI Port||micro HDMI||full HDMI|
|Microphone Port||External MIC port||External MIC port|
|Headphone Socket||no Headphone port||Headphone port|
|Wifi Support||Wifi built-in||Wifi built-in|
|Bluetooth Support||Bluetooth built-in||Bluetooth built-in|
|Body Specs||Olympus E-M5 III||Sony A7S III|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||310 shots per charge||600 shots per charge|
|In-Camera Charging||USB charging||USB charging|
125 x 85 x 50 mm
(4.9 x 3.3 x 2.0 in)
127 x 97 x 81 mm
(5.0 x 3.8 x 3.2 in)
|Camera Weight||414 g (14.6 oz)||699 g (24.7 oz)|
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