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Sony A7 II versus Olympus E-M1

The Sony Alpha A7 II and the Olympus OM-D E-M1 are two enthusiast cameras that were revealed to the public, respectively, in November 2014 and September 2013. Both the A7 II and the E-M1 are mirrorless interchangeable lens cameras that are based on a full frame (A7 II) 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 II vs Olympus E-M1

An illustration of the physical size and weight of the Sony A7 II and the Olympus E-M1 is provided in the side-by-side display below. Three consecutive views from the front, the top, and the rear side are shown. All width, height and depth measures 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 – the A7 II – represents the basis or 100 percent across all the size and weight measures).

Snapsort Sony A7 II vs Olympus E-M1
Compare A7 II versus E-M1 top
Compare A7 II 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 Sony A7 II and the Olympus E-M1are of equal size. However, the E-M1 is markedly lighter (17 percent) than the A7 II. 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 II) 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.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. If you want to switch the focus of the display and review another camera pair, just select a new right or left comparator from among the camera models in the table. Alternatively, you can also move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.

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)
Sony A7 II» 5.0 in 3.8 in 2.4 in 21.1 oz 350 Y Nov 2014 1,999- i
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 II« » 5.3 in 3.6 in 2.6 in 20.2 oz 440 Y Sep 2016 1,999 i i
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-M10« » 4.7 in 3.2 in 1.8 in 14.0 oz 320 n Jan 2014 699- i
Olympus E-P5« » 4.8 in 2.7 in 1.5 in 14.8 oz 330 n May 2013 999- i
Olympus E-M5« » 4.8 in 3.5 in 1.7 in 15.0 oz 360 Y Feb 2012 1,299- i
Sony A7 III« » 5.0 in 3.8 in 2.9 in 22.9 oz 610 Y Feb 2018 1,999 i i
Sony A9« » 5.0 in 3.8 in 2.5 in 23.7 oz 650 Y Apr 2017 4,499 i i
Sony A7R III« » 5.0 in 3.8 in 2.9 in 22.9 oz 650 Y Oct 2017 3,199 i i
Sony A7R II« » 5.0 in 3.8 in 2.4 in 22.0 oz 290 Y Jun 2015 3,199- i
Sony A7S II« » 5.0 in 3.8 in 2.4 in 22.1 oz 370 Y Sep 2015 2,999 i i
Sony A77 II« » 5.6 in 4.1 in 3.2 in 22.8 oz 480 Y May 2014 1,199 i i
Sony A7« » 5.0 in 3.7 in 1.9 in 16.7 oz 340 Y Oct 2013 1,699- i
Sony A7R« » 5.0 in 3.7 in 1.9 in 16.4 oz 340 Y Oct 2013 2,299- i
Sony A77« » 5.6 in 4.1 in 3.2 in 25.8 oz 470 Y Aug 2011 1,999- i

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 E-M1 was launched at a markedly lower price (by 30 percent) than the A7 II, 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.

 

Sensor comparison: Sony A7 II vs Olympus E-M1

The size of the imaging sensor is a crucial determinant 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Sony A7 II 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 II has a native 3:2 aspect ratio, while the one in the E-M1 offers a 4:3 aspect.

Sony A7 II and Olympus E-M1 sensor measures

With 24MP, the A7 II offers a higher resolution than the E-M1 (15.9MP), but the A7 II nevertheless has larger individual pixels (pixel pitch of 5.97μm versus 3.76μm for the E-M1) due to its larger sensor. Moreover, the A7 II is a somewhat more recent model (by 1 year and 2 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 pixels. 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 II versus E-M1 MP

For most cameras, data on sensor performance has been reported by DXO Mark. 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 review, the A7 II provides substantially higher image quality than the E-M1, with an overall score that is 17 points higher. This advantage is based on 1.9 bits higher color depth, 0.9 EV in additional dynamic range, and 1.7 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.

Sensor Characteristics
  Camera Sensor
Class
Resolution
(MP)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Sony A7 II» Full Frame 24.0 6000 40001080/60p24.913.6244990
Olympus E-M1« Four Thirds 15.9 4608 34561080/30p23.012.775773
Olympus E-M1 II« » Four Thirds 20.2 5184 38884K/30p23.712.8131280
Olympus E-M5 II« » Four Thirds 15.9 4608 34561080/60p23.012.584273
Olympus E-M10« » Four Thirds 15.9 4608 34561080/30p22.812.388472
Olympus E-P5« » Four Thirds 15.9 4608 34561080/30p22.812.489572
Olympus E-M5« » Four Thirds 15.9 4608 34561080/60i22.812.382671
Sony A7 III« » Full Frame 24.0 6000 40004K/30p25.014.7373096
Sony A9« » Full Frame 24.0 6000 40004K/30p24.913.3351792
Sony A7R III« » Full Frame 42.2 7952 53044K/30p26.014.73523100
Sony A7R II« » Full Frame 42.2 7952 53044K/30p26.013.9343498
Sony A7S II« » Full Frame 12.0 4240 28324K/30p23.613.3299385
Sony A77 II« » APS-C 24.0 6000 40001080/60p----
Sony A7« » Full Frame 24.0 6000 40001080/60p24.814.2224890
Sony A7R« » Full Frame 36.2 7360 49121080/60p25.614.1274695
Sony A77« » APS-C 24.0 6000 40001080/60p24.013.280178

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 A7 II 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 II vs Olympus E-M1

Apart from 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 II 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 II and Olympus E-M1 in connection with corresponding information for a sample of similar cameras. If you need more detail on the specs, you can find comprehensive listings, for example, in the dpreview camera hub.

Core Features
  Camera 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
Sony A7 II»2400 n 3.0 1230 tilting n 8000 5.0 n Y
Olympus E-M1«2360 n 3.0 1037 tilting Y 8000 10.0 n Y
Olympus E-M1 II« »2360 n 3.0 1037 swivel Y 8000 18.0 n Y
Olympus E-M5 II« »2360 n 3.0 1037 swivel Y 8000 10.0 n Y
Olympus E-M10« »1440 n 3.0 1037 tilting Y 4000 8.0 Y Y
Olympus E-P5« »- n 3.0 1037 tilting Y 8000 9.0 Y Y
Olympus E-M5« »1440 n 3.0 610 tilting Y 4000 9.0 n Y
Sony A7 III« »2359 n 3.0 922 tilting Y 8000 10.0 n Y
Sony A9« »3686 n 3.0 1440 tilting Y 8000 20.0 n Y
Sony A7R III« »3686 n 3.0 1440 tilting Y 8000 10.0 n Y
Sony A7R II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y
Sony A7S II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y
Sony A77 II« »2359 Y 3.0 1229 full-flex n 8000 12.0 Y Y
Sony A7« »2400 n 3.0 1230 tilting n 8000 5.0 n n
Sony A7R« »2400 n 3.0 1230 tilting n 8000 4.0 n n
Sony A77« »2359 Y 3.0 921 full-flex n 8000 12.0 Y Y

Both the A7 II 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 II was followed by the Sony A7 III.

Review summary: Sony A7 II vs Olympus E-M1

So how do things add up? Is the Sony A7 II better than the Olympus E-M1 or vice versa? The listing below highlights the relative strengths of the two models.

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Advantages of the Sony Alpha A7 II:

  • 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 (1.9 bits more color depth).
  • More dynamic range: Captures a larger spectrum of light and dark details (0.9 EV of extra DR).
  • Better low-light sensitivity: Requires less light for good images (1.7 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).
  • More modern: Is somewhat more recent (announced 1 year and 2 months after the E-M1).

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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.
  • Less heavy: Has a lower weight (by 102g or 17 percent) and is thus easier to take along.
  • More affordable: Was introduced into a lower priced category (30 percent cheaper at launch).
  • More heavily discounted: Has been on the market for longer (launched in September 2013).

If the number of relative strengths (bullet points above) is taken as a guide, the A7 II emerges as the winner of the contest (9 : 6 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 II 09:06 E-M1

In any case, while the specs-based evaluation of cameras is instructive in revealing their potential as photographic tools, it remains partial and cannot reveal, for example, the handling experience and imaging performance when actually working with the A7 II or the E-M1. 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 table below summarizes the assessments of some of the best known 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 cameralabs dpreview ephotozine imaging-resource photographyblog Camera
Launch
(announced)
Launch
Price
(USD)
Street
Price
(USD)
Used
Price
(USD)
Sony A7 II»Rec82/1004.5/55/55/5 Nov 2014 1,999- i
Olympus E-M1«HiRec84/1004.5/54.5/54.5/5 Sep 2013 1,399- i
Olympus E-M1 II« »HiRec85/1004.5/55/54.5/5 Sep 2016 1,999 i i
Olympus E-M5 II« »HiRec81/1005/54.5/55/5 Feb 2015 1,099 i i
Olympus E-M10« »-80/1005/54.5/55/5 Jan 2014 699- i
Olympus E-P5« »HiRec78/1004.5/54.5/55/5 May 2013 999- i
Olympus E-M5« »HiRec80/1004.5/55/55/5 Feb 2012 1,299- i
Sony A7 III« »HiRec89/1005/5-5/5 Feb 2018 1,999 i i
Sony A9« »HiRec89/1005/55/55/5 Apr 2017 4,499 i i
Sony A7R III« »HiRec90/1004.5/55/55/5 Oct 2017 3,199 i i
Sony A7R II« »HiRec90/1005/54.5/55/5 Jun 2015 3,199- i
Sony A7S II« »Rec-4.5/55/55/5 Sep 2015 2,999 i i
Sony A77 II« »-80/1004.5/54/55/5 May 2014 1,199 i i
Sony A7« »HiRec80/1005/54.5/55/5 Oct 2013 1,699- i
Sony A7R« »HiRec82/1004.5/55/55/5 Oct 2013 2,299- i
Sony A77« »91/10081/100-4.5/55/5 Aug 2011 1,999- i

The review scores listed above should be treated with care, though. The assessments were made in relation to similar cameras of the same technological generation. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

 

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 your choice using the following search menu. An an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool. If the camera you are interested in is not available, please send me an email, and I will try to update the database with the necessary infos.

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