Olympus E-PM1 vs Sony A77
The Olympus PEN E-PM1 and the Sony Alpha SLT-A77 are two digital cameras that were officially introduced, respectively, in June 2011 and August 2011. The E-PM1 is a mirrorless interchangeable lens camera, while the A77 is a DSLR. The cameras are based on a Four Thirds (E-PM1) and an APS-C (A77) sensor. The Olympus has a resolution of 12.2 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 PEN E-PM1 and the Sony Alpha SLT-A77? 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-PM1 and the Sony A77. 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-PM1 can be obtained in six different colors (black, silver, brown, pink, purple, white), while the A77 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 A77 is considerably larger (111 percent) than the Olympus E-PM1. Moreover, the A77 is substantially heavier (176 percent) than the E-PM1. It is noteworthy in this context that the A77 is splash and dust-proof, while the E-PM1 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. Hence, you might want to study and compare the specifications of available lenses in order to get the full picture of the size and weight of the two camera systems.
The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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.
|Olympus E-PM1||110 mm||64 mm||34 mm||265 g||330||n||Jun 2011||499|
|Sony A77||143 mm||104 mm||81 mm||732 g||470||Y||Aug 2011||1,399|
|Olympus E-PM2||110 mm||64 mm||34 mm||269 g||360||n||Sep 2012||499|
|Olympus XZ-2||113 mm||65 mm||48 mm||346 g||340||n||Sep 2012||599|
|Olympus E-P3||122 mm||69 mm||34 mm||369 g||330||n||Jun 2011||799|
|Olympus E-PL2||114 mm||72 mm||42 mm||362 g||280||n||Jan 2011||599|
|Olympus E-PL3||110 mm||64 mm||37 mm||313 g||300||n||Jun 2011||599|
|Olympus XZ-1||111 mm||65 mm||42 mm||275 g||320||n||Jan 2011||499|
|Olympus E-PL1||115 mm||72 mm||42 mm||334 g||290||n||Feb 2010||599|
|Panasonic GH5||139 mm||98 mm||87 mm||725 g||410||Y||Jan 2017||1,999|
|Panasonic GF5||108 mm||67 mm||37 mm||267 g||360||n||Apr 2012||499|
|Panasonic GF3||108 mm||67 mm||32 mm||264 g||300||n||Jun 2011||549|
|Panasonic GF2||113 mm||68 mm||33 mm||310 g||300||n||Nov 2010||549|
|Sony A9||127 mm||96 mm||63 mm||673 g||650||Y||Apr 2017||4,499|
|Sony A7 II||127 mm||96 mm||60 mm||599 g||350||Y||Nov 2014||1,999|
|Sony A77 II||143 mm||104 mm||81 mm||647 g||480||Y||May 2014||1,199|
|Sony A99||147 mm||111 mm||78 mm||812 g||500||Y||Sep 2012||2,799|
|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 manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The E-PM1 was launched at a markedly lower price (by 64 percent) than the A77, 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. 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-PM1 features a Four Thirds sensor and the Sony A77 an APS-C sensor. The sensor area in the A77 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-PM1 has a native 4:3 aspect ratio, while the one in the A77 offers a 3:2 aspect.
With 24MP, the A77 offers a higher resolution than the E-PM1 (12.2MP), but the A77 has smaller individual pixels (pixel pitch of 3.91μm versus 4.29μm for the E-PM1). It is noteworthy in this context that the two cameras were released in close succession, so that their sensors are from the same technological generation.
The resolution advantage of the Sony A77 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A77 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-PM1 are 20.2 x 15.1 inches or 51.2 x 38.4 cm for good quality, 16.1 x 12.1 inches or 41 x 30.7 cm for very good quality, and 13.4 x 10.1 inches or 34.1 x 25.6 cm for excellent quality prints.
The Olympus PEN E-PM1 has a native sensitivity range from ISO 100 to ISO 12800. The corresponding ISO settings for the Sony Alpha SLT-A77 are ISO 100 to ISO 16000, with the possibility to increase the ISO range to 50-25600.
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. Of the two cameras under consideration, the A77 offers substantially better image quality than the E-PM1 (overall score 26 points higher). The advantage is based on 3 bits higher color depth, 2.9 EV in additional dynamic range, and 0.7 stops in additional low light sensitivity. 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 |
|Olympus E-PM1||Four Thirds||12.2||4032||3024||1080/60i||21.0||10.3||499||52|
|Olympus E-PM2||Four Thirds||15.9||4608||3456||1080/30p||22.7||12.2||932||72|
|Olympus E-P3||Four Thirds||12.2||4032||3024||1080/60i||20.8||10.1||536||51|
|Olympus E-PL2||Four Thirds||12.2||4032||3024||720/30p||21.4||10.2||573||55|
|Olympus E-PL3||Four Thirds||12.2||4032||3024||1080/60i||20.9||10.3||499||52|
|Olympus E-PL1||Four Thirds||12.2||4032||3024||720/30p||21.5||10.1||487||54|
|Panasonic GH5||Four Thirds||20.2||5184||3888||4K/60p||23.9||13.0||807||77|
|Panasonic GF5||Four Thirds||12.0||4000||3000||1080/60i||21.4||11.6||618||61|
|Panasonic GF3||Four Thirds||12.0||4000||3000||1080/60i||20.6||10.0||458||49|
|Panasonic GF2||Four Thirds||12.0||4000||3000||1080/60i||21.2||10.3||506||54|
|Sony A9||Full Frame||24.0||6000||4000||4K/30p||24.9||13.3||3517||92|
|Sony A7 II||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
|Sony A77 II||APS-C||24.0||6000||4000||1080/60p||..||..||..||..|
|Sony A99||Full Frame||24.0||6000||4000||1080/60p||25.0||14.0||1555||89|
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 A77 provides a faster frame rate than the E-PM1. It can shoot movie footage at 1080/60p, while the Olympus is limited to 1080/60i.
Apart from body and sensor, cameras can and do differ across a variety of features. For example, the A77 has an electronic viewfinder (2359k dots), which can be very helpful when shooting in bright sunlight. In contrast, the E-PM1 relies on live view and the rear LCD for framing. That said, the E-PM1 can be equipped with an optional viewfinder – the VF-2. The table below summarizes some of the other core capabilities of the Olympus E-PM1 and Sony A77 in connection with corresponding information for a sample of similar cameras.
|Sony A7 II||2400||n||3.0||1230||tilting||n||1/8000s||5.0||n||Y|
|Sony A77 II||2359||Y||3.0||1229||full-flex||n||1/8000s||12.0||Y||Y|
One feature that is present on the A77, but is missing on the E-PM1 is a top-level LCD. While being, of course, smaller than the rear screen, the control panel conveys some of the essential shooting information and can be convenient for quick and easy settings verification.The A77 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-PM1 does not have a selfie-screen.
The E-PM1 writes its imaging data to SDXC cards, while the A77 uses SDXC or Memory Stick PRO Duo cards. The A77 supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the E-PM1 cannot take advantage of Ultra High Speed SD cards.
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 PEN E-PM1 and Sony Alpha SLT-A77 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|Sony A7 II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|Sony A77 II||Y||stereo||mono||Y||-||mini||2.0||Y||Y||-|
It is notable that the A77 has a microphone port, which can help to improve the quality of audio recordings by attaching an external microphone. The E-PM1 does not feature such a mic input.
Studio photographers will appreciate that the Sony A77 (unlike the E-PM1) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Travel and landscape photographers will find it useful that the A77 has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.
Both the E-PM1 and the A77 have been discontinued, but can regularly be found used on eBay. The E-PM1 was replaced by the Olympus E-PM2, while the A77 was followed by the Sony A77 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-PM1 and the Sony A77? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.
Reasons to prefer the Olympus PEN E-PM1:
- More compact: Is smaller (110x64mm vs 143x104mm) and thus needs less room in the bag.
- Less heavy: Is lighter (by 467g or 64 percent) and hence easier to carry around.
- More legacy lens friendly: Can take a broad range of non-native lenses via adapters.
- More affordable: Was introduced into a lower priced category (64 percent cheaper at launch).
Advantages of the Sony Alpha SLT-A77:
- More detail: Has more megapixels (24 vs 12.2MP), which boosts linear resolution by 43%.
- Better image quality: Scores substantially higher (26 points) in the DXO overall evaluation.
- Richer colors: Generates noticeably more natural colors (3 bits more color depth).
- More dynamic range: Captures a broader range of light and dark details (2.9 EV of extra DR).
- Better low-light sensitivity: Can shoot in dim conditions (0.7 stops ISO advantage).
- Better video: Provides higher movie framerates (1080/60p versus 1080/60i).
- 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.
- Easier setting verification: Features a control panel on top to check shooting parameters.
- More detailed LCD: Has a higher resolution rear screen (921k vs 460k dots).
- More flexible LCD: Has a full-flex screen for odd-angle shots in portrait or landscape orientation.
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Faster burst: Shoots at higher frequency (12 vs 5.5 flaps/sec) to capture the decisive moment.
- Longer lasting: Gets more shots (470 versus 330) out of a single battery charge.
- Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
- Easier fill-in: Has a small integrated flash to brighten shadows of backlit subjects.
- Easier geotagging: Features an internal GPS sensor to log localization data.
- Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
- Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
If the number of relative strengths (bullet points above) is taken as a guide, the A77 is the clear winner of the contest (20 : 4 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 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-PM1 and the Sony A77 place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera and Best DSLR Camera listings 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-PM1 or the A77 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 where reviews by experts come in. The following table reports the overall ratings of the cameras as published by some of the major camera review sites (cameralabs, dpreview, ephotozine, imaging-resource, and photographyblog). 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.
|Olympus E-PM1||86/100||71/100||4.5/5||..||4.5/5||Jun 2011||499|
|Sony A77||91/100||81/100||..||4.5/5||5/5||Aug 2011||1,399|
|Olympus E-PM2||..||77/100||5/5||4.5/5||4.5/5||Sep 2012||499|
|Olympus XZ-2||+||..||4.5/5||4/5||4.5/5||Sep 2012||599|
|Olympus E-P3||83/100||74/100||4.5/5||4.5/5||4.5/5||Jun 2011||799|
|Olympus E-PL2||83/100||71/100||4.5/5||4.5/5||4.5/5||Jan 2011||599|
|Olympus E-PL3||+ +||72/100||4.5/5||..||4/5||Jun 2011||599|
|Olympus XZ-1||..||74/100||4.5/5||4.5/5||4.5/5||Jan 2011||499|
|Olympus E-PL1||86/100||69/100||4/5||4.5/5||4.5/5||Feb 2010||599|
|Panasonic GH5||+ +||85/100||4.5/5||5/5||5/5||Jan 2017||1,999|
|Panasonic GF5||..||..||4.5/5||4/5||4.5/5||Apr 2012||499|
|Panasonic GF3||82/100||71/100||4.5/5||4.5/5||4/5||Jun 2011||549|
|Panasonic GF2||82/100||70/100||4.5/5||4.5/5||4.5/5||Nov 2010||549|
|Sony A9||+ +||89/100||5/5||5/5||5/5||Apr 2017||4,499|
|Sony A7 II||+||82/100||4.5/5||5/5||5/5||Nov 2014||1,999|
|Sony A77 II||..||80/100||4.5/5||4/5||5/5||May 2014||1,199|
|Sony A99||..||84/100||4.5/5||o||4.5/5||Sep 2012||2,799|
|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 rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. 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? 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-PM1 vs Sony A77
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-PM1||Sony A77|
|Camera Type||Mirrorless system camera||Digital single lens reflex|
|Camera Lens||Micro Four Thirds lenses||Sony A mount lenses|
|Launch Date||June 2011||August 2011|
|Launch Price||USD 499||USD 1,399|
|Sensor Specs||Olympus E-PM1||Sony A77|
|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||12.2 Megapixels||24 Megapixels|
|Image Resolution||4032 x 3024 pixels||6000 x 4000 pixels|
|Pixel Pitch||4.29 μm||3.91 μm|
|Pixel Density||5.42 MP/cm2||6.55 MP/cm2|
|Moiré control||Anti-Alias filter||Anti-Alias filter|
|Movie Capability||1080/60i Video||1080/60p Video|
|ISO Setting||100 - 12,800 ISO||100 - 16,000 ISO|
|ISO Boost||no Enhancement||50 - 25,600 ISO|
|Image Processor||TruePic VI||BIONZ X|
|DXO Sensor Quality (score)||52||78|
|DXO Color Depth (bits)||21.0||24.0|
|DXO Dynamic Range (EV)||10.3||13.2|
|DXO Low Light (ISO)||499||801|
|Screen Specs||Olympus E-PM1||Sony A77|
|Viewfinder Type||Viewfinder optional||Electronic viewfinder|
|Viewfinder Field of View||100%|
|Viewfinder Resolution||2359k dots|
|Top-Level Screen||no Top Display||Control Panel|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||460k dots||921k dots|
|LCD Attachment||Fixed screen||Fully flexible screen|
|Shooting Specs||Olympus E-PM1||Sony A77|
|Focus System||Contrast-detect AF||Phase-detect AF|
|Manual Focusing Aid||no Peaking Feature||Focus Peaking|
|Max Shutter Speed (mechanical)||1/4000s||1/8000s|
|Continuous Shooting||5.5 shutter flaps/s||12 shutter flaps/s|
|Image Stabilization||In-body stabilization||In-body stabilization|
|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||no||UHS-I|
|Connectivity Specs||Olympus E-PM1||Sony A77|
|Studio Flash||no PC Sync||PC Sync socket|
|USB Connector||USB 2.0||USB 2.0|
|HDMI Port||mini HDMI||mini HDMI|
|Microphone Port||no MIC socket||External MIC port|
|Wifi Support||no Wifi||no Wifi|
|Geotagging||no internal GPS||GPS built-in|
|Body Specs||Olympus E-PM1||Sony A77|
|Environmental Sealing||not weather sealed||Weathersealed body|
|Battery Life (CIPA)||330 shots per charge||470 shots per charge|
110 x 64 x 34 mm
(4.3 x 2.5 x 1.3 in)
143 x 104 x 81 mm
(5.6 x 4.1 x 3.2 in)
|Camera Weight||265 g (9.3 oz)||732 g (25.8 oz)|
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