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Sony A7S II versus Sony A9

The Sony Alpha 7S II and the Sony Alpha A9 are two professional cameras that were officially introduced, respectively, in September 2015 and April 2017. Both the A7S II and the A9 are mirrorless interchangeable lens cameras that are equipped with a full frame sensor. The A7S II has a resolution of 12 megapixel, whereas the A9 provides 24 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 Sony A9

The side-by-side display below illustrates the physical size and weight of the Sony A7S II and the Sony A9. 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. 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 A7S II – represents the basis or 100 percent across all the size and weight measures).

Compare Sony A7S II vs Sony A9
Compare A7S II versus A9 top
Compare A7S II and A9 rear

In this particular case, the Sony A7S II and the Sony A9 have exactly the same width and height, and, thus, have identically-sized bodies. However, the A9 is markedly heavier (7 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. In this particular case, both cameras feature the same lens mount, so that they can use the same lenses. You can find an overview of suitable optics in the Sony FE Lens Catalog. 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 A9 can take 650 images on a single charge of its NP-FZ100 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 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 A9« 5.0 in 3.8 in 2.5 in 23.7 oz 650 Y Apr 2017 4,499 i i Sony A9
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
Panasonic GH5« » 5.5 in 3.9 in 3.4 in 25.6 oz 410 Y Jan 2017 1,999 i i Panasonic GH5
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 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

Any camera purchase will naturally be influenced heavily by the price. 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 A7S II was launched at a markedly lower price (by 33 percent) than the A9, which puts it into a different market segment. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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 A7S II vs Sony A9

The size of the sensor inside a digital camera is one of the key determinants of image quality. All other things equal, a large sensor will have larger individual pixel-units that offer better low-light sensitivity, wider dynamic range, and 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.

Both cameras under consideration feature a full frame sensor and have a format factor (sometimes also referred to as "crop factor") of 1.0. Within the spectrum of camera sensors, this places the review cameras among the large-sensor cameras that aim for top notch image quality. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Sony A7S II and Sony A9 sensor measures

While the two cameras under review share the same sensor size, the A9 offers a higher resolution of 24 megapixel, compared with 12 MP of the A7S II. This megapixel advantage translates into a 42 percent gain in linear resolution. On the other hand, these sensor specs imply that the A9 has a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 5.94μm versus 8.40μm for the A7S II). However, it should be noted that the A9 is a somewhat more recent model (by 1 year and 7 months) than the A7S II, and its sensor might have benefitted from technological advances during this time that at least partly compensate for the smaller pixel size.

The A9 has on-sensor phase detect pixels, which results in relatively fast and reliable autofocus acquisition during video recording.

A7S II versus A9 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 consideration, the A9 has a markedly higher DXO score than the A7S II (overall score 7 points higher), which will translate into better image quality. The advantage is based on 1.3 bits higher color depth, and 0.2 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
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
Sony A9« Full Frame 24.0 6000 40004K/30p24.913.3351792Sony A9
Olympus E-M1 II« » Four Thirds 20.2 5184 38884K/30p23.712.8131280Olympus E-M1 II
Panasonic GH5« » Four Thirds 20.2 5184 38884K/60p23.913.080777Panasonic GH5
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 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 Sony A9

Apart from 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 A9 offers a substantially higher resolution than the one in the A7S II (3686k vs 2400k dots). The adjacent table lists some of the other core features of the Sony A7S II and Sony A9 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 A7S II»2400 n 3.0 1229 tilting n 8000 5.0 n Y Sony A7S II
Sony A9«3686 n 3.0 1440 tilting Y 8000 20.0 n Y Sony A9
Olympus E-M1 II« »2360 n 3.0 1037 swivel Y 8000 18.0 n Y Olympus E-M1 II
Panasonic GH5« »3680 n 3.2 1620 swivel Y 8000 12.0 n Y Panasonic GH5
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 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 A9 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, both cameras feature 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).

Both the A7S II and the A9 write their imaging data to SDXC or Memory Stick PRO Duo cards. The A9 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
Sony A9«YstereomonoYYmicro2.0YYYSony A9
Olympus E-M1 II« »YstereomonoYYmicro3.0Y--Olympus E-M1 II
Panasonic GH5« »YstereomonoYYfull3.1Y-YPanasonic GH5
Sony A7 III« »YstereomonoYYmicro3.1YYYSony A7 III
Sony A7R III« »YstereomonoYYmicro3.1YYYSony A7R III
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 A9 are recent models that feature in their makers' current product line-up. The A7S II replaced the earlier Sony A7S, while the A9 does not have a direct predecessor.

Review summary: Sony A7S II vs Sony A9

So how do things add up? Which of the two cameras – the Sony A7S II or the Sony A9 – has the upper hand? The listing below highlights the relative strengths of the two models.


Arguments in favor of the Sony Alpha 7S II:

  • More affordable: Was introduced into a lower priced category (33 percent cheaper at launch).
  • More heavily discounted: Has been on the market for longer (launched in September 2015).


Advantages of the Sony Alpha A9:

  • More detail: Has more megapixels (24 vs 12MP), which boosts linear resolution by 41%.
  • Better image quality: Scores markedly higher (7 points) in the DXO overall evaluation.
  • Richer colors: Generates noticeably more natural colors (1.3 bits more color depth).
  • Better video autofocus: Features on-sensor phase-detection for more confident movie autofocus.
  • More detailed viewfinder: Has higher resolution electronic viewfinder (3686k vs 2400k dots).
  • More detailed LCD: Has a higher resolution rear screen (1440k vs 1229k dots).
  • Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
  • Faster burst: Shoots at higher frequency (20 vs 5 flaps/sec) to capture the decisive moment.
  • Longer lasting: Gets more shots (650 versus 370) out of a single battery charge.
  • Easier wireless transfer: Supports Bluetooth for image sharing without cables.
  • Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
  • More modern: Was introduced somewhat (1 year and 7 months) more recently.

If the count of relative strengths (bullet points above) is taken as a measure, the A9 is the clear winner of the contest (12 : 2 points). However, the relevance of individual strengths will vary across photographers, so that you might want to apply your own weighing scheme to the summary points when reflecting and deciding on a new camera.

A7S II 02:12 A9

In any case, while the comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it remains partial and cannot reveal, for example, the handling experience and imaging performance when actually working with the A7S II or the A9. 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 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 A7S II»Rec-4.5/55/55/5 Sep 2015 2,999 i i Sony A7S II
Sony A9«HiRec89/1005/55/55/5 Apr 2017 4,499 i i Sony A9
Olympus E-M1 II« »HiRec85/1004.5/55/54.5/5 Sep 2016 1,999 i i Olympus E-M1 II
Panasonic GH5« »HiRec85/1004.5/55/55/5 Jan 2017 1,999 i i Panasonic GH5
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 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

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. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date 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. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting. If you do not see the camera that you are looking for, please contact me, and I will try to add information on that model to the database.

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