Olympus E-M5 III vs Sony A5100
The Olympus OM-D E-M5 Mark III and the Sony Alpha A5100 are two digital cameras that were officially introduced, respectively, in October 2019 and August 2014. Both the E-M5 III and the A5100 are mirrorless interchangeable lens cameras that are based on a Four Thirds (E-M5 III) and an APS-C (A5100) 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-M5 Mark III and the Sony Alpha A5100? 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 A5100. 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 dimensions are rounded to the nearest millimeter.
The E-M5 III can be obtained in two different colors (black, silver), while the A5100 is also available in two color-versions, but different ones (black, white).
If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A5100 is considerably smaller (35 percent) than the Olympus E-M5 III. Moreover, the A5100 is markedly lighter (32 percent) than the E-M5 III. It is worth mentioning in this context that the E-M5 III is splash and dust resistant, while the A5100 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-M5 III) and the Sony E-Mount Lens Catalog (A5100). 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 A5100 can take 400 images on a single charge of its NP-FW50 power pack. The battery packs of both cameras can be charged via USB, which can be very convenient when travelling.
The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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 A5100||110 mm||63 mm||36 mm||283 g||400||n||Aug 2014||549|
|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 G95||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 A5000||110 mm||63 mm||36 mm||269 g||420||n||Jan 2014||449|
|14.||Sony A6000||120 mm||67 mm||45 mm||344 g||360||n||Feb 2014||599|
|15.||Sony A3000||128 mm||91 mm||85 mm||411 g||470||n||Aug 2013||329|
|16.||Sony NEX-3N||110 mm||62 mm||35 mm||269 g||480||n||Feb 2013||499|
|17.||Sony NEX-3||117 mm||62 mm||33 mm||297 g||330||n||May 2010||599|
|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 A5100 was launched at a markedly lower price (by 54 percent) than the E-M5 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 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 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-M5 III features a Four Thirds sensor and the Sony A5100 an APS-C sensor. The sensor area in the A5100 is 63 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 1.5. The sensor in the E-M5 III has a native 4:3 aspect ratio, while the one in the A5100 offers a 3:2 aspect.
Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) sensors.
With 24MP, the A5100 offers a higher resolution than the E-M5 III (20.2MP), but the A5100 nevertheless has larger individual pixels (pixel pitch of 3.91μm versus 3.34μm for the E-M5 III) due to its larger sensor. However, the E-M5 III is a much more recent model (by 5 years and 2 months) than the A5100, and its sensor will have benefitted from technological advances during this time that 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 A5100 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A5100 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 A5100, 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 A5100 are ISO 100 to ISO 25600 (no boost).
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.
| DXO |
|1.||Olympus E-M5 III||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|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 G95||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|
Many modern cameras are not only capable of taking still images, but also of capturing video footage. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the E-M5 III provides a higher video resolution than the A5100. It can shoot video footage at 4K/30p, while the Sony is limited to 1080/60p.
Apart from body and sensor, cameras can and do differ across a variety of features. For example, the E-M5 III has an electronic viewfinder (2360k dots), which can be very helpful when shooting in bright sunlight. In contrast, the A5100 relies on live view and the rear LCD for framing. The adjacent table lists some of the other core features of the Olympus E-M5 III and Sony A5100 along with similar information for a selection of comparators.
|1.||Olympus E-M5 III||2360||n||3.0||1040||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|
|6.||Olympus E-M1 II||2360||n||3.0||1037||swivel||Y||1/8000s||18.0||n||Y|
|8.||Olympus E-M5 II||2360||n||3.0||1037||swivel||Y||1/8000s||10.0||n||Y|
One feature that differentiates the E-M5 III and the A5100 is in-body image stabilization (IBIS). The E-M5 III reduces the risk of handshake-induced blur with all attached lenses, while the A5100 offers no blur reduction with lenses that themselves do not provide optical image stabilization.Both cameras have an articulated rear screen that can be turned to be front-facing. This feature will be particularly appreciated by vloggers and photographers who are interested in taking selfies.
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, the E-M5 III is one of those camera that have an additional 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 A5100 uses SDXC or Memory Stick PRO Duo cards. The E-M5 III supports UHS-II cards (Ultra High Speed data transfer of up to 312 MB/s), while the A5100 can use UHS-I cards (up to 104 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 A5100 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|
|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|
|6.||Olympus E-M1 II||Y||stereo||mono||Y||Y||micro||3.0||Y||-||-|
|8.||Olympus E-M5 II||Y||stereo||mono||Y||-||micro||2.0||Y||-||-|
It is notable that the E-M5 III has a hotshoe, while the A5100 does not. This socket makes it possible to easily attach optional accessories, such as an external flash gun.
Both the E-M5 III and the A5100 are recent models that are part of the current product line-up. The A5100 replaced the earlier Sony A5000, while the E-M5 III followed on from the Olympus E-M5 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 what conclusions can be drawn? Is the Olympus E-M5 III better than the Sony A5100 or vice versa? A synthesis of the relative strong points of each of the models is listed below.
Arguments in favor of 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.
- Better video: Provides higher definition movie capture (4K/30p vs 1080/60p).
- Better sound: Can connect to an external microphone for higher quality sound recording.
- Easier framing: Has an electronic viewfinder for image composition and settings control.
- More detailed LCD: Has a higher resolution rear screen (1040k vs 922k dots).
- More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Faster burst: Shoots at higher frequency (10 vs 6 flaps/sec) to capture the decisive moment.
- Less disturbing: Has an electronic shutter option for completely silent shooting.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- Better sealing: Is weather sealed to enable shooting in dusty or wet environments.
- Sharper images: Has hand-shake reducing image stabilization built-in.
- Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
- Easier wireless transfer: Supports Bluetooth for image sharing without cables.
- Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
- More modern: Reflects 5 years and 2 months of technical progress since the A5100 launch.
Advantages of the Sony Alpha A5100:
- 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.
- More compact: Is smaller (110x63mm vs 125x85mm) and will fit more readily into a bag.
- Less heavy: Has a lower weight (by 131g or 32 percent) and is thus easier to take along.
- Longer lasting: Gets more shots (400 versus 310) out of a single battery charge.
- Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
- Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
- More affordable: Was introduced into a lower priced category (54 percent cheaper at launch).
- More heavily discounted: Has been around for much longer (launched in August 2014).
If the count of relative strengths (bullet points above) is taken as a measure, the E-M5 III is the clear winner of the match-up (17 : 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 A5100 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-M5 III and the A5100 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 expert reviews are important. The following table reports the overall ratings of the cameras as published by some of the major 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.
|1.||Olympus E-M5 III||5/5||+||82/100||4.5/5||4.5/5||Oct 2019||1,199|
|2.||Sony A5100||4.5/5||+||..||4.5/5||5/5||Aug 2014||549|
|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 G95||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 A5000||3/5||+||..||4.5/5||4.5/5||Jan 2014||449|
|14.||Sony A6000||5/5||+||80/100||4.5/5||5/5||Feb 2014||599|
|15.||Sony A3000||3/5||+||..||4/5||4/5||Aug 2013||329|
|16.||Sony NEX-3N||3/5||..||..||4.5/5||4.5/5||Feb 2013||499|
|17.||Sony NEX-3||..||..||70/100||4.5/5||4/5||May 2010||599|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
Care should be taken when interpreting the review scores above, though. The assessments were made in relation to similar cameras of the same technological generation. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, 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 A5100
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 A5100|
|Camera Type||Mirrorless system camera||Mirrorless system camera|
|Camera Lens||Micro Four Thirds lenses||Sony E mount lenses|
|Launch Date||October 2019||August 2014|
|Launch Price||USD 1,199||USD 549|
|Sensor Specs||Olympus E-M5 III||Sony A5100|
|Sensor Format||Four Thirds Sensor||APS-C Sensor|
|Sensor Size||17.3 x 13.0 mm||23.5 x 15.6 mm|
|Sensor Area||224.9 mm2||366.6 mm2|
|Sensor Diagonal||21.6 mm||28.2 mm|
|Sensor Resolution||20.2 Megapixels||24 Megapixels|
|Image Resolution||5184 x 3888 pixels||6000 x 4000 pixels|
|Pixel Pitch||3.34 μm||3.91 μm|
|Pixel Density||8.96 MP/cm2||6.55 MP/cm2|
|Moiré control||no AA filter||Anti-Alias filter|
|Movie Capability||4K/30p Video||1080/60p Video|
|ISO Setting||200 - 25,600 ISO||100 - 25,600 ISO|
|ISO Boost||64 - 25,600 ISO||no Enhancement|
|Image Processor||TruePic VIII||BIONZ X|
|DXO Sensor Quality (score)||..||80|
|DXO Color Depth (bits)||..||23.8|
|DXO Dynamic Range (EV)||..||12.7|
|DXO Low Light (ISO)||..||1347|
|Screen Specs||Olympus E-M5 III||Sony A5100|
|Viewfinder Type||Electronic viewfinder||no viewfinder|
|Viewfinder Field of View||100%|
|Viewfinder Resolution||2360k dots|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||1040k dots||922k dots|
|LCD Attachment||Swivel screen||Tilting screen|
|Shooting Specs||Olympus E-M5 III||Sony A5100|
|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||10 shutter flaps/s||6 shutter flaps/s|
|Electronic Shutter||up to 1/32000s||no E-Shutter|
|Time-Lapse Photography||Intervalometer built-in||no Intervalometer|
|Image Stabilization||In-body stabilization||Lens stabilization only|
|Fill Flash||no On-Board Flash||Build-in Flash|
|Storage Medium||SDXC cards||MS or SDXC cards|
|Second Storage Option||Single card slot||Single card slot|
|UHS card support||UHS-II||UHS-I|
|Connectivity Specs||Olympus E-M5 III||Sony A5100|
|External Flash||Hotshoe||no Hotshoe|
|USB Connector||USB 2.0||USB 2.0|
|HDMI Port||micro HDMI||micro HDMI|
|Microphone Port||External MIC port||no MIC socket|
|Wifi Support||Wifi built-in||Wifi built-in|
|Near-Field Communication||no NFC||NFC built-in|
|Bluetooth Support||Bluetooth built-in||no Bluetooth|
|Body Specs||Olympus E-M5 III||Sony A5100|
|Environmental Sealing||Weathersealed body||not weather sealed|
|Battery Life (CIPA)||310 shots per charge||400 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)
110 x 63 x 36 mm
(4.3 x 2.5 x 1.4 in)
|Camera Weight||414 g (14.6 oz)||283 g (10.0 oz)|
Did you notice an error on this page? If so, please get in touch, so that we can correct the information.