Olympus E-M1 III vs Sony A7C
The Olympus OM-D E-M1 Mark III and the Sony Alpha A7C are two enthusiast cameras that were officially introduced, respectively, in February 2020 and September 2020. Both the E-M1 III and the A7C are mirrorless interchangeable lens cameras that are based on a Four Thirds (E-M1 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.
Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus OM-D E-M1 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.
An illustration of the physical size and weight of the Olympus E-M1 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 successive views from the front, the top, and the rear are shown. All width, height and depth measures are rounded to the nearest millimeter.
The A7C can be obtained in two different colors (black, silver), while the E-M1 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 A7C is notably smaller (28 percent) than the Olympus E-M1 III. Moreover, the A7C is markedly lighter (12 percent) than the E-M1 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-M1 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-M1 III gets 420 shots out of its BLH-1 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 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-M1 III||134 mm||91 mm||69 mm||580 g||420||Y||Feb 2020||1,799|
|2.||Sony A7C||124 mm||71 mm||60 mm||509 g||740||Y||Sep 2020||1,799|
|3.||Fujifilm X-H1||140 mm||97 mm||86 mm||673 g||310||Y||Feb 2018||1,899|
|4.||Nikon Z6 II||134 mm||101 mm||70 mm||705 g||410||Y||Oct 2020||1,999|
|5.||Olympus E-M5 III||125 mm||85 mm||50 mm||414 g||310||Y||Oct 2019||1,199|
|6.||Olympus E-M1X||144 mm||147 mm||75 mm||997 g||870||Y||Jan 2019||2,999|
|7.||Olympus E-M1 II||134 mm||91 mm||67 mm||574 g||440||Y||Sep 2016||1,999|
|8.||Panasonic G90||130 mm||94 mm||77 mm||536 g||290||Y||Apr 2019||999|
|9.||Panasonic G9||137 mm||97 mm||92 mm||658 g||400||Y||Nov 2017||1,699|
|10.||Panasonic GH5||139 mm||98 mm||87 mm||725 g||410||Y||Jan 2017||1,999|
|11.||Sony A7 III||127 mm||96 mm||74 mm||650 g||610||Y||Feb 2018||1,999|
|12.||Sony A9||127 mm||96 mm||63 mm||673 g||650||Y||Apr 2017||4,499|
|13.||Sony A6500||120 mm||67 mm||53 mm||453 g||350||Y||Oct 2016||1,399|
|14.||Sony A7 II||127 mm||96 mm||60 mm||599 g||350||Y||Nov 2014||1,999|
|15.||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.|
Any camera decision will naturally be influenced heavily by the price. 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 two cameras under review were launched at the same price and fall into the same 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.
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 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-M1 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-M1 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-M1 III (20.2MP), but the A7C nevertheless has larger individual pixels (pixel pitch of 5.94μm versus 3.34μm for the E-M1 III) due to its larger sensor. Moreover, the A7C is a somewhat more recent model (by 7 months) than the E-M1 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-M1 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-M1 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-M1 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-M1 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.
Consistent information on actual sensor performance is available from DXO Mark for many cameras. 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 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-M1 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|
|4.||Nikon Z6 II||Full Frame||24.3||6048||4024||4K/60p||..||..||..||..|
|5.||Olympus E-M5 III||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|6.||Olympus E-M1X||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|7.||Olympus E-M1 II||Four Thirds||20.2||5184||3888||4K/30p||23.7||12.8||1312||80|
|8.||Panasonic G90||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|9.||Panasonic G9||Four Thirds||20.2||5184||3888||4K/60p||..||..||..||..|
|10.||Panasonic GH5||Four Thirds||20.2||5184||3888||4K/60p||23.9||13.0||807||77|
|11.||Sony A7 III||Full Frame||24.0||6000||4000||4K/30p||25.0||14.7||3730||96|
|12.||Sony A9||Full Frame||24.0||6000||4000||4K/30p||24.9||13.3||3517||92|
|14.||Sony A7 II||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
|15.||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. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, and both provide the same movie specifications (4K/30p).
Beyond body and sensor, cameras can and do differ across a range of features. The E-M1 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-M1 III and Sony A7C in connection with corresponding information for a sample of similar cameras.
|1.||Olympus E-M1 III||2360||n||3.0||1037||swivel||Y||1/8000s||18.0||n||Y|
|4.||Nikon Z6 II||3690||Y||3.2||2100||tilting||Y||1/8000s||14.0||n||Y|
|5.||Olympus E-M5 III||2360||n||3.0||1040||swivel||Y||1/8000s||10.0||n||Y|
|7.||Olympus E-M1 II||2360||n||3.0||1037||swivel||Y||1/8000s||18.0||n||Y|
|11.||Sony A7 III||2359||n||3.0||922||tilting||Y||1/8000s||10.0||n||Y|
|14.||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 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-M1 III writes its imaging data to SDXC cards, while the A7C uses SDXC or Memory Stick PRO Duo cards. The E-M1 III features dual card slots, which can be very useful in case a memory card fails. In contrast, the A7C only has one slot. Both cameras support UHS-II cards, which provide for Ultra High Speed data transfer of up to 312 MB/s (the second slot of the E-M1 III supports only UHS-I, though).
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 III and Sony Alpha A7C and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|1.||Olympus E-M1 III||Y||stereo||mono||Y||Y||micro||3.1||Y||-||Y|
|4.||Nikon Z6 II||Y||stereo||mono||Y||Y||micro||3.2||Y||-||Y|
|5.||Olympus E-M5 III||Y||stereo||mono||Y||-||micro||2.0||Y||-||Y|
|7.||Olympus E-M1 II||Y||stereo||mono||Y||Y||micro||3.0||Y||-||-|
|11.||Sony A7 III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|14.||Sony A7 II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
Studio photographers will appreciate that the Olympus E-M1 III (unlike the A7C) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Both the E-M1 III and the A7C are recent models that are part of the current product line-up. The E-M1 III replaced the earlier Olympus E-M1 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.
So what conclusions can be drawn? Is the Olympus E-M1 III better than the Sony A7C or vice versa? Below is a summary of the relative strengths of each of the two contestants.
Advantages of the Olympus OM-D E-M1 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 (0.83x vs 0.59x).
- More detailed LCD: Has a higher resolution rear screen (1037k vs 922k dots).
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Faster burst: Shoots at higher frequency (18 vs 10 flaps/sec) to capture the decisive moment.
- Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
- Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
- More heavily discounted: Has been on the market for longer (launched in February 2020).
Reasons to prefer 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.
- More compact: Is smaller (124x71mm vs 134x91mm) and will fit more readily into a bag.
- Less heavy: Has a lower weight (by 71g or 12 percent) and is thus easier to take along.
- Longer lasting: Gets more shots (740 versus 420) out of a single battery charge.
- Faster data transfer: Supports a more advanced USB protocol (3.2 vs 3.1).
- Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
- More modern: Was introduced somewhat (7 months) more recently.
If the count of individual advantages (bullet points above) is taken as a guide, the A7C emerges as the winner of the match-up (12 : 9 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 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-M1 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 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-M1 III and the A7C in practical situations. 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 hands-on reviews by experts 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 III||5/5||..||83/100||4.5/5||4/5||Feb 2020||1,799|
|2.||Sony A7C||3.5/5||..||86/100||4/5||4/5||Sep 2020||1,799|
|3.||Fujifilm X-H1||..||+||86/100||4.5/5||4.5/5||Feb 2018||1,899|
|4.||Nikon Z6 II||4.5/5||..||89/100||4.5/5||4.5/5||Oct 2020||1,999|
|5.||Olympus E-M5 III||5/5||+||82/100||4.5/5||4.5/5||Oct 2019||1,199|
|6.||Olympus E-M1X||4.5/5||o||..||4.5/5||..||Jan 2019||2,999|
|7.||Olympus E-M1 II||5/5||+ +||85/100||4.5/5||4.5/5||Sep 2016||1,999|
|8.||Panasonic G90||4.5/5||+||83/100||4.5/5||4.5/5||Apr 2019||999|
|9.||Panasonic G9||..||+ +||85/100||5/5||5/5||Nov 2017||1,699|
|10.||Panasonic GH5||4.5/5||+ +||85/100||4.5/5||5/5||Jan 2017||1,999|
|11.||Sony A7 III||..||+ +||89/100||5/5||5/5||Feb 2018||1,999|
|12.||Sony A9||5/5||+ +||89/100||5/5||5/5||Apr 2017||4,499|
|13.||Sony A6500||5/5||+ +||85/100||4.5/5||4.5/5||Oct 2016||1,399|
|14.||Sony A7 II||5/5||+||82/100||4.5/5||5/5||Nov 2014||1,999|
|15.||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 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.
Specifications: Olympus E-M1 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.
|Camera Model||Olympus E-M1 III||Sony A7C|
|Camera Type||Mirrorless system camera||Mirrorless system camera|
|Camera Lens||Micro Four Thirds lenses||Sony E mount lenses|
|Launch Date||February 2020||September 2020|
|Launch Price||USD 1,799||USD 1,799|
|Sensor Specs||Olympus E-M1 III||Sony A7C|
|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||24 Megapixels|
|Image Resolution||5184 x 3888 pixels||6000 x 4000 pixels|
|Pixel Pitch||3.34 μm||5.94 μm|
|Pixel Density||8.96 MP/cm2||2.83 MP/cm2|
|Moiré control||no AA filter||Anti-Alias filter|
|Movie Capability||4K/30p Video||4K/30p Video|
|ISO Setting||200 - 25,600 ISO||100 - 51,200 ISO|
|ISO Boost||64 - 25,600 ISO||50 - 204,800 ISO|
|Image Processor||TruePic IX||BIONZ X|
|DXO Sensor Quality (score)||..||95|
|DXO Color Depth (bits)||..||25.0|
|DXO Dynamic Range (EV)||..||14.7|
|DXO Low Light (ISO)||..||3407|
|Screen Specs||Olympus E-M1 III||Sony A7C|
|Viewfinder Type||Electronic viewfinder||Electronic viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||2360k dots||2360k dots|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||1037k dots||922k dots|
|LCD Attachment||Swivel screen||Swivel screen|
|Shooting Specs||Olympus E-M1 III||Sony A7C|
|Focus System||On-Sensor Phase-detect||On-Sensor Phase-detect|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/8000s||1/4000s|
|Continuous Shooting||18 shutter flaps/s||10 shutter flaps/s|
|Shutter Life Expectancy||400 000 actuations||200 000 actuations|
|Electronic Shutter||up to 1/32000s||up to 1/8000s|
|Time-Lapse Photography||Intervalometer built-in||Intervalometer built-in|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||no On-Board Flash||no On-Board Flash|
|Storage Medium||SDXC cards||MS or SDXC cards|
|Second Storage Option||Dual card slots||Single card slot|
|UHS card support||Single UHS-II||UHS-II|
|Connectivity Specs||Olympus E-M1 III||Sony A7C|
|Studio Flash||PC Sync socket||no PC Sync|
|USB Connector||USB 3.1||USB 3.2|
|HDMI Port||micro HDMI||micro HDMI|
|Microphone Port||External MIC port||External MIC port|
|Headphone Socket||Headphone port||Headphone port|
|Wifi Support||Wifi built-in||Wifi built-in|
|Near-Field Communication||no NFC||NFC built-in|
|Bluetooth Support||Bluetooth built-in||Bluetooth built-in|
|Body Specs||Olympus E-M1 III||Sony A7C|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||420 shots per charge||740 shots per charge|
|In-Camera Charging||USB charging||USB charging|
134 x 91 x 69 mm
(5.3 x 3.6 x 2.7 in)
124 x 71 x 60 mm
(4.9 x 2.8 x 2.4 in)
|Camera Weight||580 g (20.5 oz)||509 g (18.0 oz)|
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