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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 consecutive perspectives from the front, the top, and the back are available. All size dimensions are rounded to the nearest millimeter. If you prefer, you can also use the toggle button to switch to a comparison in percentage terms (in this case, the camera on the left side – the A7 – represents the basis for the calculations 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 table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. 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 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-M10« » 4.7 in 3.2 in 1.8 in 14.0 oz 320 n Jan 2014 699- i Olympus E-M10
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 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 A5100« » 4.3 in 2.5 in 1.4 in 10.0 oz 400 n Aug 2014 549 i i Sony A5100
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

The camera’s price is obviously a critical decision-making factor. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. 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. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.

 

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 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. 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 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.

In terms of underlying technology, both cameras are build around CMOS 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 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 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 adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.

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 E-M5 II« » Four Thirds 15.9 4608 34561080/60p23.012.584273Olympus E-M5 II
Olympus E-M10« » Four Thirds 15.9 4608 34561080/30p22.812.388472Olympus E-M10
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 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 A5100« » APS-C 24.0 6000 40001080/60p23.812.7134780Sony A5100
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. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, 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 table below summarizes some of the other core capabilities of the Sony A7 and Olympus E-M1 in connection with corresponding information for a sample of similar cameras. If needed, the dpreview camera hub, for example, contains further detail on the cameras' specs.

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 E-M5 II« »2360 n 3.0 1037 swivel Y 8000 10.0 n Y Olympus E-M5 II
Olympus E-M10« »1440 n 3.0 1037 tilting Y 4000 8.0 Y Y Olympus E-M10
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 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 A5100« »- n 3.0 922 tilting Y 4000 6.0 Y n Sony A5100
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

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 how do things add up? Is there a clear favorite between the Sony A7 and the Olympus E-M1? A synthesis of the relative strong points of each of the models is listed below.

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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).
  • More detailed LCD: Has a higher resolution rear screen (1230k vs 1037k dots).

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Reasons to prefer 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 relative strengths (bullet points above) is taken as a measure, the A7 emerges as the winner of the contest (8 : 5 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features before making a decision on a new camera.

A7 08:05 E-M1

In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it says nothing about, for example, the handling, responsiveness, and overall imaging quality of the A7 and the E-M1 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 where reviews by experts come in. The following table reports the overall rankings of the cameras as published by some of the major camera review sites (cameralabs, dpreview, ephotozine, imaging-resource, photographyblog). The detailed reviews can be accessed 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 E-M5 II« »HiRec81/1005/54.5/55/5 Feb 2015 1,099 i i Olympus E-M5 II
Olympus E-M10« »-80/1005/54.5/55/5 Jan 2014 699- i Olympus E-M10
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 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 A5100« »Rec-4.5/54.5/55/5 Aug 2014 549 i i Sony A5100
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

The above review scores should be interpreted with care, though. The assessments were made in relation to similar cameras of the same technological generation. Thus, a score needs to be put into the context of the launch date and the launch price 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? In case you would like to check on the differences and similarities of other camera models, just make your choice using the following search menu. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored. If the camera you are interested in is not available, please contact me, and I will try to add information on that model to the database.

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