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Sony A7S II versus Olympus E-M1 II

The Sony Alpha 7S II and the Olympus OM-D E-M1 Mark II are two digital cameras that were announced, respectively, in September 2015 and September 2016. Both the A7S II and the E-M1 II are mirrorless interchangeable lens cameras that are based on a full frame (A7S II) and a Four Thirds (E-M1 II) sensor. The Sony has a resolution of 12 megapixel, whereas the Olympus provides 20.2 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 A7S II vs Olympus E-M1 II

An illustration of the physical size and weight of the Sony A7S II and the Olympus E-M1 II is provided 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 side – the A7S II – represents the basis for the calculations across all the size and weight measures).

Compare Sony A7S II vs Olympus E-M1 II
Compare A7S II versus E-M1 II top
Compare A7S II and E-M1 II rear

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7S II and the Olympus E-M1 II are of equal size. However, the E-M1 II is markedly lighter (8 percent) than the A7S 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 (A7S II) and the Micro Four Thirds Lens Catalog (E-M1 II). 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 A7S II gets 370 shots out of its NP-FW50 battery, while the E-M1 II can take 440 images on a single charge of its BLH-1 power pack.

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, just use the right or left arrows in the table to switch to the respective camera. Alternatively, you can also navigate to the CAM-parator app and make your selection from the full list of cameras 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
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
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-M1« » 5.1 in 3.7 in 2.5 in 17.5 oz 350 Y Sep 2013 1,399- i Olympus E-M1
Panasonic G9« » 5.4 in 3.8 in 3.6 in 23.2 oz 400 Y Nov 2017 1,699 i i Panasonic G9
Panasonic GH5« » 5.5 in 3.9 in 3.4 in 25.6 oz 410 Y Jan 2017 1,999 i i Panasonic GH5
Panasonic GX8« » 5.2 in 3.1 in 2.5 in 17.2 oz 330 Y Jul 2015 1,199- i Panasonic GX8
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 A7R III« » 5.0 in 3.8 in 2.9 in 22.9 oz 650 Y Oct 2017 3,199 i i Sony A7R III
Sony A9« » 5.0 in 3.8 in 2.5 in 23.7 oz 650 Y Apr 2017 4,499 i i Sony A9
Sony A99 II« » 5.6 in 4.1 in 3.0 in 29.9 oz 490 Y Sep 2016 3,199 i i Sony A99 II
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 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 A99« » 5.8 in 4.4 in 3.1 in 28.6 oz 500 Y Sep 2012 2,799- i Sony A99
Sony A900« » 6.1 in 4.6 in 3.2 in 31.6 oz 880 Y Sep 2008 2,999- i Sony A900

The camera’s price is obviously a critical decision-making factor. 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-M1 II was launched at a markedly lower price (by 33 percent) than the A7S 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.

 

Sensor comparison: Sony A7S II vs Olympus E-M1 II

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 Sony A7S II features a full frame sensor and the Olympus E-M1 II a Four Thirds sensor. The sensor area in the E-M1 II is 73 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 A7S II has a native 3:2 aspect ratio, while the one in the E-M1 II offers a 4:3 aspect.

Sony A7S II and Olympus E-M1 II sensor measures

Despite having a smaller sensor, the E-M1 II offers a higher resolution of 20.2 megapixel, compared with 12 MP of the A7S II. 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 3.34μm versus 8.40μm for the A7S II). However, it should be noted that the E-M1 II is a somewhat more recent model (by 1 year) than the A7S II, 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-M1 II has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

Unlike the A7S II, the E-M1 II has the capacity to capture high quality composite images (50MP) by combining multiple shots after shifting its sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).

A7S II versus E-M1 II MP

For many 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 A7S II has a notably higher overall DXO score than the E-M1 II (overall score 5 points higher), which gives it an advantage in terms of imaging quality. This advantage is based on 0.099999999999998 bits lower color depth, 0.5 EV in additional dynamic range, and 1.2 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 A7S II» Full Frame 12.0 4240 28324K/30p23.613.3299385Sony A7S II
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-M1« » Four Thirds 15.9 4608 34561080/30p23.012.775773Olympus E-M1
Panasonic G9« » Four Thirds 20.2 5184 38884K/60p----Panasonic G9
Panasonic GH5« » Four Thirds 20.2 5184 38884K/60p23.913.080777Panasonic GH5
Panasonic GX8« » Four Thirds 20.2 5184 38884K/30p23.512.680675Panasonic GX8
Sony A7 III« » Full Frame 24.0 6000 40004K/30p25.014.7373096Sony A7 III
Sony A7R III« » Full Frame 42.2 7952 53044K/30p26.014.73523100Sony A7R III
Sony A9« » Full Frame 24.0 6000 40004K/30p24.913.3351792Sony A9
Sony A99 II« » Full Frame 42.2 7952 53044K/30p25.413.4231792Sony A99 II
Sony A7R II« » Full Frame 42.2 7952 53044K/30p26.013.9343498Sony A7R II
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 A99« » Full Frame 24.0 6000 40001080/60p25.014.0155589Sony A99
Sony A900« » Full Frame 24.4 6048 4032-23.712.3143179Sony A900

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, and both provide the same movie specifications (4K/30p).

 

Feature comparison: Sony A7S II vs Olympus E-M1 II

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 A7S II offers a slightly higher resolution than the one in the E-M1 II (2400k vs 2360k dots). The adjacent table lists some of the other core features of the Sony A7S II and Olympus E-M1 II along with similar information for a selection of comparators. 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 A7S II»2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7S II
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-M1« »2360 n 3.0 1037 tilting Y 8000 10.0 n Y Olympus E-M1
Panasonic G9« »3680 Y 3.0 1040 swivel Y 8000 20.0 n Y Panasonic G9
Panasonic GH5« »3680 n 3.2 1620 swivel Y 8000 12.0 n Y Panasonic GH5
Panasonic GX8« »2360 n 3.0 1040 swivel Y 8000 10.0 n Y Panasonic GX8
Sony A7 III« »2359 n 3.0 922 tilting Y 8000 10.0 n Y Sony A7 III
Sony A7R III« »3686 n 3.0 1440 tilting Y 8000 10.0 n Y Sony A7R III
Sony A9« »3686 n 3.0 1440 tilting Y 8000 20.0 n Y Sony A9
Sony A99 II« »2400 Y 3.0 1229 full-flex n 8000 12.0 n Y Sony A99 II
Sony A7R II« »2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7R II
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 A99« »2359 Y 3.0 1229 full-flex n 8000 6.0 n Y Sony A99
Sony A900« »optical Y 3.0 922 fixed n 8000 5.0 n Y Sony A900

One differentiating feature between the two cameras concerns the touch sensitivity of the rear screen. The E-M1 II has a touchscreen, while the A7S II has a conventional panel. Touch control can be particularly helpful, for example, for setting the focus point.

The reported shutter speed and shutter burst refer to the use of the mechanical shutter. In addition, the E-M1 II features an electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (rolling shutter) or shooting under artificial light sources (flickering).

The A7S II writes its imaging data to SDXC or Memory Stick PRO Duo cards, while the E-M1 II uses SDXC cards. The E-M1 II features dual card slots, which can be very useful in case a memory card fails. In contrast, the A7S II only has one slot.

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 A7S II»YstereomonoYYmicro2.0YY-Sony A7S II
Olympus E-M1 II«YstereomonoYYmicro3.0Y--Olympus E-M1 II
Olympus E-M5 II« »YstereomonoY-micro2.0Y--Olympus E-M5 II
Olympus E-M1« »YstereomonoY-micro2.0Y--Olympus E-M1
Panasonic G9« »YstereomonoYYfull3.0Y-YPanasonic G9
Panasonic GH5« »YstereomonoYYfull3.1Y-YPanasonic GH5
Panasonic GX8« »YstereomonoY-micro2.0YY-Panasonic GX8
Sony A7 III« »YstereomonoYYmicro3.1YYYSony A7 III
Sony A7R III« »YstereomonoYYmicro3.1YYYSony A7R III
Sony A9« »YstereomonoYYmicro2.0YYYSony A9
Sony A99 II« »YstereomonoYYmicro2.0YYYSony A99 II
Sony A7R II« »YstereomonoYYmicro2.0YY-Sony A7R II
Sony A7 II« »YstereomonoYYmicro2.0YY-Sony A7 II
Sony A7S« »YstereomonoYYmicro2.0YY-Sony A7S
Sony A99« »YstereomonoYYmini2.0---Sony A99
Sony A900« »Y----mini2.0---Sony A900

Both the A7S II and the E-M1 II are current models that good online retailers will have in stock. You can check the latest prices, for example, at amazon. The A7S II replaced the earlier Sony A7S, while the E-M1 II followed on from the Olympus E-M1.

Review summary: Sony A7S II vs Olympus E-M1 II

So what conclusions can be drawn? Is the Sony A7S II better than the Olympus E-M1 II or vice versa? The listing below highlights the relative strengths of the two models.

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Arguments in favor of the Sony Alpha 7S II:

  • Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
  • Better image quality: Scores markedly higher (5 points) in the DXO overall assessment.
  • Better low-light sensitivity: Requires less light for good images (1.2 stops ISO advantage).
  • More detailed LCD: Has a higher resolution rear screen (1229k vs 1037k dots).
  • 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 September 2015).

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Advantages of the Olympus OM-D E-M1 Mark II:

  • More detail: Has more megapixels (20.2 vs 12MP), which boosts linear resolution by 27%.
  • Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
  • High quality composites: Can combine several shots after pixel-shifting its sensor.
  • More flexible LCD: Has swivel screen for odd-angle shots in portrait or landscape orientation.
  • Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
  • Faster burst: Shoots at higher frequency (18 vs 5 flaps/sec) to capture the decisive moment.
  • Less disturbing: Has an electronic shutter option for completely silent shooting.
  • Longer lasting: Gets more shots (440 versus 370) out of a single battery charge.
  • Faster data transfer: Supports a more advanced USB protocol (3.0 vs 2.0).
  • Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
  • More affordable: Was introduced into a lower priced category (33 percent cheaper at launch).
  • More modern: Was introduced somewhat (1 year) more recently.

If the count of relative strengths (bullet points above) is taken as a measure, the E-M1 II is the clear winner of the contest (12 : 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.

A7S II 06:12 E-M1 II

In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it remains partial and cannot reveal, for example, the handling experience and imaging performance when actually working with the A7S II or the E-M1 II. 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 why expert reviews are important. 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 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 A7S II»Rec-4.5/55/55/5 Sep 2015 2,999 i i Sony A7S II
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-M1« »HiRec84/1004.5/54.5/54.5/5 Sep 2013 1,399- i Olympus E-M1
Panasonic G9« »HiRec85/1005/55/55/5 Nov 2017 1,699 i i Panasonic G9
Panasonic GH5« »HiRec85/1004.5/55/55/5 Jan 2017 1,999 i i Panasonic GH5
Panasonic GX8« »Rec82/1004.5/55/54.5/5 Jul 2015 1,199- i Panasonic GX8
Sony A7 III« »HiRec89/1005/55/55/5 Feb 2018 1,999 i i Sony A7 III
Sony A7R III« »HiRec90/1004.5/55/55/5 Oct 2017 3,199 i i Sony A7R III
Sony A9« »HiRec89/1005/55/55/5 Apr 2017 4,499 i i Sony A9
Sony A99 II« »-85/1004.5/54.5/54.5/5 Sep 2016 3,199 i i Sony A99 II
Sony A7R II« »HiRec90/1005/54.5/55/5 Jun 2015 3,199- i Sony A7R II
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 A99« »-84/1004.5/5rev4.5/5 Sep 2012 2,799- i Sony A99
Sony A900« »HiRecHiRec4.5/54/55/5 Sep 2008 2,999- i Sony A900

The above review scores should be interpreted with care, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. 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 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 do not see the camera that you are looking for, please contact me, and I will try to update the database with the necessary infos.

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