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Olympus E-M10 II versus Sony A7S

The Olympus OM-D E-M10 Mark II and the Sony Alpha A7S are two digital cameras that were revealed to the public, respectively, in August 2015 and April 2014. Both the E-M10 II and the A7S are mirrorless interchangeable lens cameras that are based on a Four Thirds (E-M10 II) and a full frame (A7S) sensor. The Olympus has a resolution of 15.9 megapixel, whereas the Sony provides 12 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: Olympus E-M10 II vs Sony A7S

The physical size and weight of the Olympus E-M10 II and the Sony A7S are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive views from the front, the top, and the rear side 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 E-M10 II – represents 100 percent across all the size and weight measures).

Compare Olympus E-M10 II vs Sony A7S
Compare E-M10 II versus A7S top
Compare E-M10 II and A7S rear

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7S is notably larger (20 percent) than the Olympus E-M10 II. Moreover, the A7S is markedly heavier (25 percent) than the E-M10 II. It is noteworthy in this context that the A7S is splash and dust-proof, while the E-M10 II 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 find an overview of optics for the two cameras in the Micro Four Thirds Lens Catalog (E-M10 II) and the Sony FE Lens Catalog (A7S). 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-M10 II gets 320 shots out of its BLS-50 battery, while the A7S can take 380 images on a single charge of its NP-FW50 power pack.

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)
Camera
Model
Olympus E-M10 II» 4.7 in 3.3 in 1.9 in 13.8 oz 320 n Aug 2015 799- i Olympus E-M10 II
Sony A7S« 5.0 in 3.7 in 1.9 in 17.2 oz 380 Y Apr 2014 2,499- i Sony A7S
Olympus E-PL9« » 4.6 in 2.7 in 1.5 in 13.4 oz 350 n Feb 2018 549 i i Olympus E-PL9
Olympus E-M10 III« » 4.8 in 3.3 in 2.0 in 14.5 oz 330 n Aug 2017 649 i i Olympus E-M10 III
Olympus E-PL8« » 4.5 in 2.6 in 1.5 in 12.6 oz 350 n Sep 2016 549- i Olympus E-PL8
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-M10« » 4.7 in 3.2 in 1.8 in 14.0 oz 320 n Jan 2014 699- i Olympus E-M10
Olympus E-PL7« » 4.5 in 2.6 in 1.5 in 12.6 oz 350 n Aug 2014 599- i Olympus E-PL7
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-PL5« » 4.4 in 2.5 in 1.5 in 11.5 oz 360 n Sep 2012 599- i Olympus E-PL5
Panasonic GX85« » 4.8 in 2.8 in 1.7 in 15.0 oz 290 n Apr 2016 799 i i Panasonic GX85
Sony A7R II« » 5.0 in 3.8 in 2.4 in 22.0 oz 290 Y Jun 2015 3,199- i Sony A7R II
Sony A7S II« » 5.0 in 3.8 in 2.4 in 22.1 oz 370 Y Sep 2015 2,999 i i Sony A7S II
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 A7« » 5.0 in 3.7 in 1.9 in 16.7 oz 340 Y Oct 2013 1,699- i Sony A7
Sony A7R« » 5.0 in 3.7 in 1.9 in 16.4 oz 340 Y Oct 2013 2,299- i Sony A7R

The price is, of course, an important factor in any camera decision. 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-M10 II was launched at a markedly lower price (by 68 percent) than the A7S, 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.

 

Sensor comparison: Olympus E-M10 II vs Sony A7S

The size of the imaging sensor is a crucial determinant 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. 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-M10 II features a Four Thirds sensor and the Sony A7S a full frame sensor. The sensor area in the A7S is 280 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 1.0. The sensor in the E-M10 II has a native 4:3 aspect ratio, while the one in the A7S offers a 3:2 aspect.

Olympus E-M10 II and Sony A7S sensor measures

Despite having a smaller sensor, the Olympus E-M10 II offers a higher resolution of 15.9 megapixel, compared with 12 MP of the Sony A7S. This megapixel advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.76μm versus 8.45μm for the A7S). However, it should be noted that the E-M10 II is a somewhat more recent model (by 1 year and 4 months) than the A7S, and its sensor might have benefitted from technological advances during this time that partly offset its pixel-size disadvantage. Coming back to sensor resolution, it should be mentioned that the E-M10 II has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

E-M10 II versus A7S 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 consideration, the A7S offers substantially better image quality than the E-M10 II (overall score 14 points higher). The advantage is based on 0.8 bits higher color depth, 0.7 EV in additional dynamic range, and 2.1 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
Olympus E-M10 II» Four Thirds 15.9 4608 34561080/60p23.112.584273Olympus E-M10 II
Sony A7S« Full Frame 12.0 4240 28321080/60p23.913.2370287Sony A7S
Olympus E-PL9« » Four Thirds 15.9 4608 34564K/30p----Olympus E-PL9
Olympus E-M10 III« » Four Thirds 15.9 4608 34564K/30p----Olympus E-M10 III
Olympus E-PL8« » Four Thirds 15.9 4608 34561080/30p----Olympus E-PL8
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-M10« » Four Thirds 15.9 4608 34561080/30p22.812.388472Olympus E-M10
Olympus E-PL7« » Four Thirds 15.9 4608 34561080/30p22.712.487372Olympus E-PL7
Olympus E-P5« » Four Thirds 15.9 4608 34561080/30p22.812.489572Olympus E-P5
Olympus E-PL5« » Four Thirds 15.9 4608 34561080/30p22.812.388972Olympus E-PL5
Panasonic GX85« » Four Thirds 15.8 4592 34484K/30p22.912.666271Panasonic GX85
Sony A7R II« » Full Frame 42.2 7952 53044K/30p26.013.9343498Sony A7R II
Sony A7S II« » Full Frame 12.0 4240 28324K/30p23.613.3299385Sony A7S II
Sony A7 II« » Full Frame 24.0 6000 40001080/60p24.913.6244990Sony A7 II
Sony A7« » Full Frame 24.0 6000 40001080/60p24.814.2224890Sony A7
Sony A7R« » Full Frame 36.2 7360 49121080/60p25.614.1274695Sony A7R

Many modern cameras are not only capable of taking still images, but also of capturing video footage. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, and both provide the same movie specifications (1080/60p).

 

Feature comparison: Olympus E-M10 II vs Sony A7S

Beyond body and sensor, cameras can and do differ across a range of features. The two cameras under review are similar with respect to both having an electronic viewfinder. However, the one in the A7S offers a slightly higher resolution than the one in the E-M10 II (2400k vs 2360k dots). The adjacent table lists some of the other core features of the Olympus E-M10 II and Sony A7S 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
Olympus E-M10 II»2360 n 3.0 1040 tilting Y 4000 8.0 Y Y Olympus E-M10 II
Sony A7S«2400 n 3.0 921 tilting n 8000 5.0 n n Sony A7S
Olympus E-PL9« »- n 3.0 1040 tilting Y 4000 8.6 Y Y Olympus E-PL9
Olympus E-M10 III« »2360 n 3.0 1040 tilting Y 4000 8.6 Y Y Olympus E-M10 III
Olympus E-PL8« »- n 3.0 1037 tilting Y 4000 8.0 n Y Olympus E-PL8
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-M10« »1440 n 3.0 1037 tilting Y 4000 8.0 Y Y Olympus E-M10
Olympus E-PL7« »- n 3.0 1037 tilting Y 4000 8.0 n Y Olympus E-PL7
Olympus E-P5« »- n 3.0 1037 tilting Y 8000 9.0 Y Y Olympus E-P5
Olympus E-PL5« »- n 3.0 460 tilting Y 4000 8.0 n Y Olympus E-PL5
Panasonic GX85« »2765 n 3.0 1040 tilting Y 4000 8.0 Y Y Panasonic GX85
Sony A7R II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7R II
Sony A7S II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7S II
Sony A7 II« »2400 n 3.0 1230 tilting n 8000 5.0 n Y Sony A7 II
Sony A7« »2400 n 3.0 1230 tilting n 8000 5.0 n n Sony A7
Sony A7R« »2400 n 3.0 1230 tilting n 8000 4.0 n n Sony A7R

One difference between the cameras concerns the presence of an on-board flash. The E-M10 II has one, while the A7S does not. While the build-in flash of the E-M10 II is not very powerful, it can at times be useful as a fill-in light.

The E-M10 II writes its imaging data to SDXC cards, while the A7S uses SDXC or Memory Stick PRO Duo 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
Olympus E-M10 II»Ystereomono--micro2.0Y--Olympus E-M10 II
Sony A7S«YstereomonoYYmicro2.0YY-Sony A7S
Olympus E-PL9« »Ystereomono--micro2.0Y-YOlympus E-PL9
Olympus E-M10 III« »Ystereomono--micro2.0Y--Olympus E-M10 III
Olympus E-PL8« »Ystereomono--micro2.0Y--Olympus E-PL8
Olympus PEN-F« »Ystereomono--micro2.0Y--Olympus PEN-F
Olympus E-M5 II« »YstereomonoY-micro2.0Y--Olympus E-M5 II
Olympus E-M10« »Ystereomono--micro2.0Y--Olympus E-M10
Olympus E-PL7« »Ystereomono--micro2.0Y--Olympus E-PL7
Olympus E-P5« »Ystereomono--micro2.0Y--Olympus E-P5
Olympus E-PL5« »Ystereomono--mini2.0---Olympus E-PL5
Panasonic GX85« »Ystereomono--micro2.0YY-Panasonic GX85
Sony A7R II« »YstereomonoYYmicro2.0YY-Sony A7R II
Sony A7S II« »YstereomonoYYmicro2.0YY-Sony A7S II
Sony A7 II« »YstereomonoYYmicro2.0YY-Sony A7 II
Sony A7« »YstereomonoYYmicro2.0YY-Sony A7
Sony A7R« »YstereomonoYYmicro2.0YY-Sony A7R

Both the E-M10 II and the A7S have been discontinued, but can regularly be found used on eBay. The A7S was replaced by the Sony A7S II, while the E-M10 II was followed by the Olympus E-M10 III.

Review summary: Olympus E-M10 II vs Sony A7S

So what conclusions can be drawn? Is there a clear favorite between the Olympus E-M10 II and the Sony A7S? The listing below highlights the relative strengths of the two models.

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Arguments in favor of the Olympus OM-D E-M10 Mark II:

  • More detail: Offers more megapixels (15.9 vs 12MP) with a 13% higher linear resolution.
  • Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
  • More detailed LCD: Has a higher resolution rear screen (1040k vs 921k dots).
  • Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
  • Faster burst: Shoots at higher frequency (8 vs 5 flaps/sec) to capture the decisive moment.
  • More compact: Is smaller (120x83mm vs 127x94mm) and thus needs less room in the bag.
  • Less heavy: Is lighter (by 99g or 20 percent) and hence easier to carry around.
  • Sharper images: Has hand-shake reducing image stabilization build-in.
  • Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
  • More affordable: Was introduced into a lower priced category (68 percent cheaper at launch).
  • More modern: Is somewhat more recent (announced 1 year and 4 months after the A7S).

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Advantages of the Sony Alpha A7S:

  • Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
  • Better image quality: Scores substantially higher (14 points) in the DXO overall evaluation.
  • More dynamic range: Captures a broader range of light and dark details (0.7 EV of extra DR).
  • Better low-light sensitivity: Can shoot in dim conditions (2.1 stops ISO advantage).
  • Better sound: Can connect to an external microphone for higher quality sound recording.
  • Better sound control: Has a headphone port that enables audio monitoring while recording.
  • Faster shutter: Has higher mechanical shutter speed (8000/sec vs 4000/sec) to freeze action.
  • Longer lasting: Gets more shots (380 versus 320) out of a single battery charge.
  • Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
  • Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
  • More heavily discounted: Has been on the market for longer (launched in April 2014).

If the count of relative strengths (bullet points above) is taken as a measure, the match-up finishes in a tie (11 points each). 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.

E-M10 II 11:11 A7S

In any case, while the specs-based evaluation of cameras is instructive in revealing their potential as photographic tools, it says nothing about, for example, the handling, responsiveness, and overall imaging quality of the E-M10 II and the A7S 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 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
Olympus E-M10 II»HiRec80/1005/55/55/5 Aug 2015 799- i Olympus E-M10 II
Sony A7S«-86/1004.5/54.5/55/5 Apr 2014 2,499- i Sony A7S
Olympus E-PL9« »Rec-4.5/5-4/5 Feb 2018 549 i i Olympus E-PL9
Olympus E-M10 III« »Rec80/1004.5/54/54.5/5 Aug 2017 649 i i Olympus E-M10 III
Olympus E-PL8« »--4.5/5-4/5 Sep 2016 549- i Olympus E-PL8
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-M10« »-80/1005/54.5/55/5 Jan 2014 699- i Olympus E-M10
Olympus E-PL7« »Rec-5/54.5/54/5 Aug 2014 599- i Olympus E-PL7
Olympus E-P5« »HiRec78/1004.5/54.5/55/5 May 2013 999- i Olympus E-P5
Olympus E-PL5« »HiRec-4.5/54.5/54.5/5 Sep 2012 599- i Olympus E-PL5
Panasonic GX85« »HiRec82/1005/54.5/55/5 Apr 2016 799 i i Panasonic GX85
Sony A7R II« »HiRec90/1005/54.5/55/5 Jun 2015 3,199- i Sony A7R II
Sony A7S II« »Rec-4.5/55/55/5 Sep 2015 2,999 i i Sony A7S II
Sony A7 II« »Rec82/1004.5/55/55/5 Nov 2014 1,999- i Sony A7 II
Sony A7« »HiRec80/1005/54.5/55/5 Oct 2013 1,699- i Sony A7
Sony A7R« »HiRec82/1004.5/55/55/5 Oct 2013 2,299- i Sony A7R

The review scores listed above should be treated with care, though. The ratings are only valid when referring to cameras in the same category and of the same age. 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, please note that some of the review sites have changed their methodology and reporting over time.

 

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. 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, kindly get in touch, and I will try to locate and add the respective data to the application.

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