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Sony A7 versus Olympus E-M1

The Sony Alpha A7 and the Olympus OM-D E-M1 are two enthusiast cameras that were revealed to the public, respectively, in October 2013 and September 2013. Both the A7 and the E-M1 are mirrorless interchangeable lens cameras that are based on a full frame (A7) and a Four Thirds (E-M1) sensor. The Sony has a resolution of 24 megapixel, whereas the Olympus provides 15.9 MP. Read on to find out how these two cameras compare with respect to their size, their sensors, their features, and their reception by expert reviewers.

Body comparison: Sony A7 vs Olympus E-M1

An illustration of the physical size and weight of the Sony A7 and the Olympus E-M1 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 size dimensions are rounded to the nearest millimeter. You can also use the toggle button to switch to a percentage comparison if you prefer that the measures are being expressed in relative terms (in this case, the camera on the left – the A7 – represents 100 percent across all the size and weight measures).

Compare Sony A7 vs Olympus E-M1
Compare A7 versus E-M1 top
Compare A7 and E-M1 rear

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Olympus E-M1 is somewhat larger (2 percent) than the Sony A7. Moreover, the E-M1 is markedly heavier (5 percent) than the A7. 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 find an overview of optics for the two cameras in the Sony FE Lens Catalog (A7) and the Micro Four Thirds Lens Catalog (E-M1). 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 A7 gets 340 shots out of its NP-FW50 battery, while the E-M1 can take 350 images on a single charge of its BLN-1 power pack.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. In case you want to display and compare another camera duo, just click on the right or left arrow next to the camera that you would like to inspect. Alternatively, you can also use the CAM-parator to select your camera combination among a larger number of options.

Camera Body Specifications
  Camera
Model
Camera
Width
Camera
Height
Camera
Depth
Camera
Weight
Battery
Life
(CIPA)
Weather
Sealing
(yes/no)
Camera
Launch
(announced)
Launch
Price
(USD)
Street
Price
(USD)
Used
Price
(USD)
Camera
Model
Sony A7» 5.0 in 3.7 in 1.9 in 16.7 oz 340 Y Oct 2013 1,699- i Sony A7
Olympus E-M1« 5.1 in 3.7 in 2.5 in 17.5 oz 350 Y Sep 2013 1,399- i Olympus E-M1
Nikon D610« » 5.6 in 4.4 in 3.2 in 30.0 oz 900 Y Oct 2013 1,999 i i Nikon D610
Olympus E-M1 II« » 5.3 in 3.6 in 2.6 in 20.2 oz 440 Y Sep 2016 1,999 i i Olympus E-M1 II
Olympus PEN-F« » 4.9 in 2.8 in 1.5 in 15.1 oz 330 n Jan 2016 1,199 i i Olympus PEN-F
Olympus E-M5 II« » 4.9 in 3.3 in 1.8 in 16.5 oz 310 Y Feb 2015 1,099 i i Olympus E-M5 II
Olympus E-P5« » 4.8 in 2.7 in 1.5 in 14.8 oz 330 n May 2013 999- i Olympus E-P5
Olympus E-M5« » 4.8 in 3.5 in 1.7 in 15.0 oz 360 Y Feb 2012 1,299- i Olympus E-M5
Panasonic GH4« » 5.2 in 3.7 in 3.3 in 19.8 oz 500 Y Feb 2014 1,499- i Panasonic GH4
Sony A7 III« » 5.0 in 3.8 in 2.9 in 22.9 oz 610 Y Feb 2018 1,999 i i Sony A7 III
Sony A6300« » 4.7 in 2.6 in 1.9 in 14.3 oz 400 Y Feb 2016 999- i Sony A6300
Sony A6500« » 4.7 in 2.6 in 2.1 in 16.0 oz 350 Y Oct 2016 1,399 i i Sony A6500
Sony A7 II« » 5.0 in 3.8 in 2.4 in 21.1 oz 350 Y Nov 2014 1,999- i Sony A7 II
Sony A7S« » 5.0 in 3.7 in 1.9 in 17.2 oz 380 Y Apr 2014 2,499- i Sony A7S
Sony A7R« » 5.0 in 3.7 in 1.9 in 16.4 oz 340 Y Oct 2013 2,299- i Sony A7R
Sony RX1R« » 4.4 in 2.6 in 2.8 in 17.0 oz 270 n Jun 2013 2,799- i Sony RX1R
Sony RX1« » 4.4 in 2.6 in 2.8 in 17.0 oz 270 n Sep 2012 2,799- i Sony RX1

Any camera purchase 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 E-M1 was launched at a somewhat lower price (by 18 percent) than the A7, which makes it more attractive for photographers on a tight budget. 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.

 

Sensor comparison: Sony A7 vs Olympus E-M1

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 tend to be more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Sony A7 features a full frame sensor and the Olympus E-M1 a Four Thirds sensor. The sensor area in the E-M1 is 74 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 2.0. The sensor in the A7 has a native 3:2 aspect ratio, while the one in the E-M1 offers a 4:3 aspect.

Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) sensors.

Sony A7 and Olympus E-M1 sensor measures

With 24MP, the A7 offers a higher resolution than the E-M1 (15.9MP), but the A7 nevertheless has larger individual pixels (pixel pitch of 5.97μm versus 3.76μm for the E-M1) due to its larger sensor. 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. 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.

A7 versus E-M1 MP

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"). Of the two cameras under review, the A7 provides substantially higher image quality than the E-M1, with an overall score that is 17 points higher. This advantage is based on 1.8 bits higher color depth, 1.5 EV in additional dynamic range, and 1.6 stops in additional low light sensitivity. The following table provides an overview of the physical sensor characteristics, as well as the sensor quality measurements for a selection of comparators.

Sensor Characteristics
  Camera
Model
Sensor
Class
Resolution
(MP)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Camera
Model
Sony A7» Full Frame 24.0 6000 40001080/60p24.814.2224890Sony A7
Olympus E-M1« Four Thirds 15.9 4608 34561080/30p23.012.775773Olympus E-M1
Nikon D610« » Full Frame 24.2 6016 40161080/30p25.114.4292594Nikon D610
Olympus E-M1 II« » Four Thirds 20.2 5184 38884K/30p23.712.8131280Olympus E-M1 II
Olympus PEN-F« » Four Thirds 20.2 5184 38881080/60p23.112.489474Olympus PEN-F
Olympus E-M5 II« » Four Thirds 15.9 4608 34561080/60p23.012.584273Olympus E-M5 II
Olympus E-P5« » Four Thirds 15.9 4608 34561080/30p22.812.489572Olympus E-P5
Olympus E-M5« » Four Thirds 15.9 4608 34561080/60i22.812.382671Olympus E-M5
Panasonic GH4« » Four Thirds 15.9 4608 34564K/30p23.212.879174Panasonic GH4
Sony A7 III« » Full Frame 24.0 6000 40004K/30p25.014.7373096Sony A7 III
Sony A6300« » APS-C 24.0 6000 40004K/30p24.413.7143785Sony A6300
Sony A6500« » APS-C 24.0 6000 40004K/30p24.513.7140585Sony A6500
Sony A7 II« » Full Frame 24.0 6000 40001080/60p24.913.6244990Sony A7 II
Sony A7S« » Full Frame 12.0 4240 28321080/60p23.913.2370287Sony A7S
Sony A7R« » Full Frame 36.2 7360 49121080/60p25.614.1274695Sony A7R
Sony RX1R« » Full Frame 24.0 6000 40001080/60p25.013.6253791Sony RX1R
Sony RX1« » Full Frame 24.0 6000 40001080/60p25.114.3253493Sony RX1

Many modern cameras are not only capable of taking still images, but can also record movies. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the A7 provides a higher frame rate than the E-M1. It can shoot video footage at 1080/60p, while the Olympus is limited to 1080/30p.

 

Feature comparison: Sony A7 vs Olympus E-M1

Beyond body and sensor, cameras can and do differ across a range of features. The two cameras under consideration are similar with respect to both having an electronic viewfinder. However, the one in the A7 offers a slightly higher resolution than the one in the E-M1 (2400k vs 2360k dots). The adjacent table lists some of the other core features of the Sony A7 and Olympus E-M1 along with similar information for a selection of comparators. If you need more detail on the specs, you can find comprehensive listings, for example, in the dpreview camera hub.

Core Features
  Camera
Model
Viewfinder
(Type or
'000 dots)
Control
Panel
(yes/no)
LCD
Size
(inch)
LCD
Resolution
('000 dots)
LCD
Attach-
ment
Touch
Screen
(yes/no)
Shutter
speed
(1/sec)
Shutter
flaps
(1/sec)
Build-in
Flash
(yes/no)
Build-in
Image
Stab
Camera
Model
Sony A7»2400 n 3.0 1230 tilting n 8000 5.0 n n Sony A7
Olympus E-M1«2360 n 3.0 1037 tilting Y 8000 10.0 n Y Olympus E-M1
Nikon D610« »optical Y 3.2 921 fixed n 4000 6.0 Y n Nikon D610
Olympus E-M1 II« »2360 n 3.0 1037 swivel Y 8000 18.0 n Y Olympus E-M1 II
Olympus PEN-F« »2360 n 3.0 1037 swivel Y 8000 10.0 n Y Olympus PEN-F
Olympus E-M5 II« »2360 n 3.0 1037 swivel Y 8000 10.0 n Y Olympus E-M5 II
Olympus E-P5« »- n 3.0 1037 tilting Y 8000 9.0 Y Y Olympus E-P5
Olympus E-M5« »1440 n 3.0 610 tilting Y 4000 9.0 n Y Olympus E-M5
Panasonic GH4« »2359 n 3.0 1036 swivel Y 8000 12.0 Y n Panasonic GH4
Sony A7 III« »2359 n 3.0 922 tilting Y 8000 10.0 n Y Sony A7 III
Sony A6300« »2300 n 3.0 922 tilting n 4000 11.0 Y n Sony A6300
Sony A6500« »2300 n 3.0 922 tilting Y 4000 11.0 Y Y Sony A6500
Sony A7 II« »2400 n 3.0 1230 tilting n 8000 5.0 n Y Sony A7 II
Sony A7S« »2400 n 3.0 921 tilting n 8000 5.0 n n Sony A7S
Sony A7R« »2400 n 3.0 1230 tilting n 8000 4.0 n n Sony A7R
Sony RX1R« »- n 3.0 1229 fixed n 4000 5.0 Y n Sony RX1R
Sony RX1« »- n 3.0 1229 fixed n 4000 5.0 Y n Sony RX1

One differentiating feature between the two cameras concerns the touch sensitivity of the rear screen. The E-M1 has a touchscreen, while the A7 has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.

The A7 writes its imaging data to SDXC or Memory Stick PRO Duo cards, while the E-M1 uses SDXC cards.

Input-Output Connections
  Camera
Model
Hotshoe
Port
Internal
Microphone
Internal
Speaker
Microphone
Port
Headphone
Port
HDMI
Port
USB
Type
WiFi
Support
NFC
Support
Bluetooth
Support
Camera
Model
Sony A7»YstereomonoYYmicro2.0YY-Sony A7
Olympus E-M1«YstereomonoY-micro2.0Y--Olympus E-M1
Nikon D610« »YmonomonoYYmini2.0---Nikon D610
Olympus E-M1 II« »YstereomonoYYmicro3.0Y--Olympus E-M1 II
Olympus PEN-F« »Ystereomono--micro2.0Y--Olympus PEN-F
Olympus E-M5 II« »YstereomonoY-micro2.0Y--Olympus E-M5 II
Olympus E-P5« »Ystereomono--micro2.0Y--Olympus E-P5
Olympus E-M5« »Ystereomono--mini2.0---Olympus E-M5
Panasonic GH4« »YstereomonoYYmicro2.0YY-Panasonic GH4
Sony A7 III« »YstereomonoYYmicro3.1YYYSony A7 III
Sony A6300« »YstereomonoY-micro2.0YY-Sony A6300
Sony A6500« »YstereomonoY-micro2.0YY-Sony A6500
Sony A7 II« »YstereomonoYYmicro2.0YY-Sony A7 II
Sony A7S« »YstereomonoYYmicro2.0YY-Sony A7S
Sony A7R« »YstereomonoYYmicro2.0YY-Sony A7R
Sony RX1R« »YstereomonoY-mini2.0---Sony RX1R
Sony RX1« »YstereomonoY-mini2.0---Sony RX1

Both the A7 and the E-M1 have been discontinued, but can regularly be found used on eBay. The E-M1 was replaced by the Olympus E-M1 II, while the A7 was followed by the Sony A7 II.

Review summary: Sony A7 vs Olympus E-M1

So what is the bottom line? Which of the two cameras – the Sony A7 or the Olympus E-M1 – has the upper hand? Below is a summary of the relative strengths of each of the two contestants.

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Advantages of the Sony Alpha A7:

  • More detail: Offers more megapixels (24 vs 15.9MP) with a 25% higher linear resolution.
  • Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
  • Better image quality: Scores substantially higher (17 points) in the DXO overall assessment.
  • Richer colors: Generates images with noticeably better colors (1.8 bits more color depth).
  • More dynamic range: Captures a larger spectrum of light and dark details (1.5 EV of extra DR).
  • Better low-light sensitivity: Requires less light for good images (1.6 stops ISO advantage).
  • Better video: Provides higher movie framerates (1080/60p versus 1080/30p).
  • Better sound control: Has a headphone port that enables audio monitoring while recording.
  • More detailed LCD: Has a higher resolution rear screen (1230k vs 1037k dots).
  • Easier device pairing: Supports NFC for fast wireless image transfer over short distances.

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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.
  • Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
  • Faster burst: Shoots at higher frequency (10 vs 5 flaps/sec) to capture the decisive moment.
  • Sharper images: Has stabilization technology build-in to reduce the impact of hand-shake.
  • More affordable: Was released into a lower priced segment (18 percent cheaper at launch).

If the count of individual advantages (bullet points above) is taken as a guide, the A7 is the clear winner of the match-up (10 : 5 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.

A7 10:05 E-M1

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 A7 or the E-M1 handle or perform in practice. At times, user reviews, such as those published at amazon, address these issues in a useful manner, but such feedback is on many occasions incomplete, inconsistent, and unreliable. This is where reviews by experts come in. The table below summarizes the assessments of some of the best known camera review sites (cameralabs, dpreview, ephotozine, imaging-resource, photographyblog). The full reviews are available by clicking on the site logo in the table header.

Review Scores
  Camera
Model
cameralabs dpreview ephotozine imaging-resource photographyblog Camera
Launch
(announced)
Launch
Price
(USD)
Street
Price
(USD)
Used
Price
(USD)
Camera
Model
Sony A7»HiRec80/1005/54.5/55/5 Oct 2013 1,699- i Sony A7
Olympus E-M1«HiRec84/1004.5/54.5/54.5/5 Sep 2013 1,399- i Olympus E-M1
Nikon D610« »HiRec87/1004.5/54.5/54.5/5 Oct 2013 1,999 i i Nikon D610
Olympus E-M1 II« »HiRec85/1004.5/55/54.5/5 Sep 2016 1,999 i i Olympus E-M1 II
Olympus PEN-F« »-82/1004.5/54.5/55/5 Jan 2016 1,199 i i Olympus PEN-F
Olympus E-M5 II« »HiRec81/1005/54.5/55/5 Feb 2015 1,099 i i Olympus E-M5 II
Olympus E-P5« »HiRec78/1004.5/54.5/55/5 May 2013 999- i Olympus E-P5
Olympus E-M5« »HiRec80/1004.5/55/55/5 Feb 2012 1,299- i Olympus E-M5
Panasonic GH4« »HiRec85/1005/55/55/5 Feb 2014 1,499- i Panasonic GH4
Sony A7 III« »HiRec89/1005/55/55/5 Feb 2018 1,999 i i Sony A7 III
Sony A6300« »Rec85/1005/55/55/5 Feb 2016 999- i Sony A6300
Sony A6500« »HiRec85/1004.5/55/54.5/5 Oct 2016 1,399 i i Sony A6500
Sony A7 II« »Rec82/1004.5/55/55/5 Nov 2014 1,999- i Sony A7 II
Sony A7S« »-86/1004.5/54.5/55/5 Apr 2014 2,499- i Sony A7S
Sony A7R« »HiRec82/1004.5/55/55/5 Oct 2013 2,299- i Sony A7R
Sony RX1R« »--4/5rev4.5/5 Jun 2013 2,799- i Sony RX1R
Sony RX1« »-79/1004/54.5/54.5/5 Sep 2012 2,799- i Sony RX1

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 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. If you cannot find the camera you are interested in, please send me an email, and I will try to add information on that model to the database.

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