Olympus E-M1 vs Sony A5100
The Olympus OM-D E-M1 and the Sony Alpha A5100 are two digital cameras that were revealed to the public, respectively, in September 2013 and August 2014. Both the E-M1 and the A5100 are mirrorless interchangeable lens cameras that are based on a Four Thirds (E-M1) and an APS-C (A5100) sensor. The Olympus has a resolution of 15.9 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 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 physical size and weight of the Olympus E-M1 and the Sony A5100 are illustrated 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 size dimensions are rounded to the nearest millimeter.
The E-M1 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 (43 percent) than the Olympus E-M1. Moreover, the A5100 is substantially lighter (43 percent) than the E-M1. It is worth mentioning in this context that the E-M1 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-M1) 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-M1 gets 350 shots out of its BLN-1 battery, while the A5100 can take 400 images on a single charge of its NP-FW50 power pack. The power pack in the A5100 can be charged via the USB port, 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 would like to visualize and compare a different camera combination, you can navigate to the CAM-parator app and make your selection from a broad list of cameras there.
|1.||Olympus E-M1||130 mm||94 mm||63 mm||497 g||350||Y||Sep 2013||1,399|
|2.||Sony A5100||110 mm||63 mm||36 mm||283 g||400||n||Aug 2014||549|
|3.||Olympus E-M1 II||134 mm||91 mm||67 mm||574 g||440||Y||Sep 2016||1,999|
|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-PL7||115 mm||67 mm||38 mm||357 g||350||n||Aug 2014||599|
|7.||Olympus E-P5||122 mm||69 mm||37 mm||420 g||330||n||May 2013||999|
|8.||Olympus E-M5||122 mm||89 mm||43 mm||425 g||360||Y||Feb 2012||1,299|
|9.||Olympus E-PL5||111 mm||64 mm||38 mm||325 g||360||n||Sep 2012||599|
|10.||Olympus E-PM2||110 mm||64 mm||34 mm||269 g||360||n||Sep 2012||499|
|11.||Panasonic GH4||133 mm||93 mm||84 mm||560 g||500||Y||Feb 2014||1,499|
|12.||Panasonic GH3||133 mm||93 mm||82 mm||550 g||540||Y||Sep 2012||1,299|
|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.|
Any camera decision will naturally be influenced heavily by the price. 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 61 percent) than the E-M1, 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.
The size of the sensor inside a digital camera is one of the key determinants 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. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to isolate a subject from the 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 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-M1 has a native 4:3 aspect ratio, while the one in the A5100 offers a 3:2 aspect.
With 24MP, the A5100 offers a higher resolution than the E-M1 (15.9MP), but the A5100 nevertheless has larger individual pixels (pixel pitch of 3.91μm versus 3.76μm for the E-M1) due to its larger sensor. Moreover, the A5100 is a somewhat more recent model (by 11 months) than the E-M1, 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 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-M1 are 23 x 17.3 inches or 58.5 x 43.9 cm for good quality, 18.4 x 13.8 inches or 46.8 x 35.1 cm for very good quality, and 15.4 x 11.5 inches or 39 x 29.3 cm for excellent quality prints.
The Olympus OM-D E-M1 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 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 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"). Of the two cameras under consideration, the A5100 has a markedly higher DXO score than the E-M1 (overall score 7 points higher), which will translate into better image quality. The advantage is based on 0.8 bits higher color depth, and 0.8 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||Four Thirds||15.9||4608||3456||1080/30p||23.0||12.7||757||73|
|3.||Olympus E-M1 II||Four Thirds||20.2||5184||3888||4K/30p||23.7||12.8||1312||80|
|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-PL7||Four Thirds||15.9||4608||3456||1080/30p||22.7||12.4||873||72|
|7.||Olympus E-P5||Four Thirds||15.9||4608||3456||1080/30p||22.8||12.4||895||72|
|8.||Olympus E-M5||Four Thirds||15.9||4608||3456||1080/60i||22.8||12.3||826||71|
|9.||Olympus E-PL5||Four Thirds||15.9||4608||3456||1080/30p||22.8||12.3||889||72|
|10.||Olympus E-PM2||Four Thirds||15.9||4608||3456||1080/30p||22.7||12.2||932||72|
|11.||Panasonic GH4||Four Thirds||15.9||4608||3456||4K/30p||23.2||12.8||791||74|
|12.||Panasonic GH3||Four Thirds||15.9||4608||3456||1080/60p||22.7||12.4||812||71|
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 A5100 provides a faster frame rate than the E-M1. It can shoot movie footage at 1080/60p, while the Olympus is limited to 1080/30p.
Apart from body and sensor, cameras can and do differ across a variety of features. For example, the E-M1 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-M1 and Sony A5100 along with similar information for a selection of comparators.
|3.||Olympus E-M1 II||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|
One feature that differentiates the E-M1 and the A5100 is in-body image stabilization (IBIS). The E-M1 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.The A5100 has an articulated screen that can be turned to be front-facing. This characteristic will be appreciated by vloggers and photographers who are interested in taking selfies. In contrast, the E-M1 does not have a selfie-screen.
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-M1 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-M1 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 writes its imaging data to SDXC cards, while the A5100 uses SDXC or Memory Stick PRO Duo cards. Both cameras can use UHS-I cards, which provide for Ultra High Speed data transfer of 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-M1 and Sony Alpha A5100 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|3.||Olympus E-M1 II||Y||stereo||mono||Y||Y||micro||3.0||Y||-||-|
|5.||Olympus E-M5 II||Y||stereo||mono||Y||-||micro||2.0||Y||-||-|
It is notable that the E-M1 has a hotshoe, while the A5100 does not. This socket makes it possible to easily attach optional accessories, such as an external flash gun.
Studio photographers will appreciate that the Olympus E-M1 (unlike the A5100) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
The A5100 is a recent model that features in the current product line-up of Sony. In contrast, the E-M1 has been discontinued (but can be found pre-owned on eBay). As a replacement in the same line of cameras, the E-M1 was succeeded by the Olympus E-M1 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 there a clear favorite between the Olympus E-M1 and the Sony A5100? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.
Arguments in favor of the Olympus OM-D E-M1:
- Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
- 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 (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 (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.
- Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
- More heavily discounted: Has been on the market for longer (launched in September 2013).
Advantages of the Sony Alpha A5100:
- More detail: Has more megapixels (24 vs 15.9MP), which boosts linear resolution by 25%.
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- Better image quality: Scores markedly higher (7 points) in the DXO overall evaluation.
- Better low-light sensitivity: Can shoot in dim conditions (0.8 stops ISO advantage).
- Better video: Provides higher movie framerates (1080/60p versus 1080/30p).
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- More compact: Is smaller (110x63mm vs 130x94mm) and will fit more readily into a bag.
- Less heavy: Has a lower weight (by 214g or 43 percent) and is thus easier to take along.
- Longer lasting: Gets more shots (400 versus 350) out of a single battery charge.
- Easier travel charging: Can be conveniently charged via its USB port.
- 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 (61 percent cheaper at launch).
- More modern: Was introduced somewhat (11 months) more recently.
If the count of individual advantages (bullet points above) is taken as a guide, the A5100 comes out slightly ahead of the E-M1 (14 : 13 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 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 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 or the A5100 perform in practice. 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.
This is why hands-on reviews by experts 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-M1||5/5||+ +||84/100||4.5/5||4.5/5||Sep 2013||1,399|
|2.||Sony A5100||4.5/5||+||..||4.5/5||5/5||Aug 2014||549|
|3.||Olympus E-M1 II||5/5||+ +||85/100||4.5/5||4.5/5||Sep 2016||1,999|
|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-PL7||4/5||+||..||5/5||4/5||Aug 2014||599|
|7.||Olympus E-P5||5/5||+ +||78/100||4.5/5||5/5||May 2013||999|
|8.||Olympus E-M5||4/5||+ +||80/100||4.5/5||5/5||Feb 2012||1,299|
|9.||Olympus E-PL5||3/5||+ +||..||4.5/5||4.5/5||Sep 2012||599|
|10.||Olympus E-PM2||3/5||..||77/100||5/5||4.5/5||Sep 2012||499|
|11.||Panasonic GH4||5/5||+ +||85/100||5/5||5/5||Feb 2014||1,499|
|12.||Panasonic GH3||5/5||+ +||79/100||4.5/5||4.5/5||Sep 2012||1,299|
|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.|
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. 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, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.
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 use the search menu below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.
Specifications: Olympus E-M1 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-M1||Sony A5100|
|Camera Type||Mirrorless system camera||Mirrorless system camera|
|Camera Lens||Micro Four Thirds lenses||Sony E mount lenses|
|Launch Date||September 2013||August 2014|
|Launch Price||USD 1,399||USD 549|
|Sensor Specs||Olympus E-M1||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||15.9 Megapixels||24 Megapixels|
|Image Resolution||4608 x 3456 pixels||6000 x 4000 pixels|
|Pixel Pitch||3.76 μm||3.91 μm|
|Pixel Density||7.08 MP/cm2||6.55 MP/cm2|
|Moiré control||no AA filter||Anti-Alias filter|
|Movie Capability||1080/30p Video||1080/60p Video|
|ISO Setting||200 - 25,600 ISO||100 - 25,600 ISO|
|ISO Boost||100 - 25,600 ISO||no Enhancement|
|Image Processor||TruePIC VII||BIONZ X|
|DXO Sensor Quality (score)||73||80|
|DXO Color Depth (bits)||23.0||23.8|
|DXO Dynamic Range (EV)||12.7||12.7|
|DXO Low Light (ISO)||757||1347|
|Screen Specs||Olympus E-M1||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||1037k dots||922k dots|
|LCD Attachment||Tilting screen||Tilting screen|
|Shooting Specs||Olympus E-M1||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||YES||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-I||UHS-I|
|Connectivity Specs||Olympus E-M1||Sony A5100|
|External Flash||Hotshoe||no Hotshoe|
|Studio Flash||PC Sync socket||no PC Sync|
|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|
|Body Specs||Olympus E-M1||Sony A5100|
|Environmental Sealing||Weathersealed body||not weather sealed|
|Battery Life (CIPA)||350 shots per charge||400 shots per charge|
|In-Camera Charging||no USB charging||USB charging|
130 x 94 x 63 mm
(5.1 x 3.7 x 2.5 in)
110 x 63 x 36 mm
(4.3 x 2.5 x 1.4 in)
|Camera Weight||497 g (17.5 oz)||283 g (10.0 oz)|
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