Sony A7S II vs 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 megapixels, whereas the A9 provides 24 MP.
Below is an overview of the main specs of the two cameras as a starting point for the comparison.
Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha 7S II and the Sony Alpha A9? Which one should you buy? Read on to find out how these two cameras compare with respect to their body size, their imaging sensors, their shooting features, their input-output connections, and their reception by expert reviewers.
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.
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 compare the optics available 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 battery packs of both cameras can be charged via USB, which can be very convenient when travelling.
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, you can use the CAM-parator app to select your camera combination among a large number of options.
|1.||Sony A7S II||127 mm||96 mm||60 mm||627 g||370||Y||Sep 2015||2,999||ebay.com|
|2.||Sony A9||127 mm||96 mm||63 mm||673 g||650||Y||Apr 2017||4,499||ebay.com|
|3.||Sony A7 IV||131 mm||96 mm||80 mm||659 g||580||Y||Oct 2021||2,499||amazon.com|
|4.||Sony A7S III||127 mm||97 mm||81 mm||699 g||600||Y||Jul 2020||3,499||amazon.com|
|5.||Sony A9 II||129 mm||96 mm||76 mm||678 g||690||Y||Oct 2019||4,499||amazon.com|
|6.||Sony A7R IV||129 mm||96 mm||78 mm||665 g||670||Y||Jul 2019||3,499||amazon.com|
|7.||Sony A7 III||127 mm||96 mm||74 mm||650 g||610||Y||Feb 2018||1,999||amazon.com|
|8.||Sony A7R III||127 mm||96 mm||74 mm||650 g||650||Y||Oct 2017||3,199||ebay.com|
|9.||Sony A99 II||143 mm||104 mm||76 mm||849 g||490||Y||Sep 2016||3,199||ebay.com|
|10.||Sony A7R II||127 mm||96 mm||60 mm||625 g||290||Y||Jun 2015||3,199||ebay.com|
|11.||Sony A7 II||127 mm||96 mm||60 mm||599 g||350||Y||Nov 2014||1,999||ebay.com|
|12.||Sony A7S||127 mm||94 mm||48 mm||489 g||380||Y||Apr 2014||2,499||ebay.com|
|Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
Any camera decision 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.
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.
While the two cameras under review share the same sensor size, the A9 offers a higher resolution of 24 megapixels, compared with 12 MP of the A7S II. This megapixels 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 resolution advantage of the Sony A9 implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A9 for good quality output (200 dots per inch) amounts to 30 x 20 inches or 76.2 x 50.8 cm, for very good quality (250 dpi) 24 x 16 inches or 61 x 40.6 cm, and for excellent quality (300 dpi) 20 x 13.3 inches or 50.8 x 33.9 cm. The corresponding values for the Sony A7S II are 21.2 x 14.2 inches or 53.8 x 36 cm for good quality, 17 x 11.3 inches or 43.1 x 28.8 cm for very good quality, and 14.1 x 9.4 inches or 35.9 x 24 cm for excellent quality prints.
The A9 has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.
The Sony Alpha 7S II has a native sensitivity range from ISO 100 to ISO 102400, which can be extended to ISO 50-409600. The corresponding ISO settings for the Sony Alpha A9 are ISO 100 to ISO 51200, with the possibility to increase the ISO range to 50-204800.
In terms of underlying technology, the A7S II is build around a CMOS sensor, while the A9 uses a Stacked BSI-CMOS imager. Both cameras use a Bayer filter for capturing RGB colors on a square grid of photosensors. This arrangement is found in most digital cameras.
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.
|1.||Sony A7S II||Full Frame||12.0||4240||2832||4K/30p||23.6||13.3||2993||85|
|2.||Sony A9||Full Frame||24.0||6000||4000||4K/30p||24.9||13.3||3517||92|
|3.||Sony A7 IV||Full Frame||32.7||7008||4672||4K/60p||25.4||14.7||3379||97|
|4.||Sony A7S III||Full Frame||12.0||4240||2832||4K/120p||23.7||13.9||2520||86|
|5.||Sony A9 II||Full Frame||24.0||6000||4000||4K/30p||25.0||14.0||3434||93|
|6.||Sony A7R IV||Full Frame||60.2||9504||6336||4K/30p||26.0||14.8||3344||99|
|7.||Sony A7 III||Full Frame||24.0||6000||4000||4K/30p||25.0||14.7||3730||96|
|8.||Sony A7R III||Full Frame||42.2||7952||5304||4K/30p||26.0||14.7||3523||100|
|9.||Sony A99 II||Full Frame||42.2||7952||5304||4K/30p||25.4||13.4||2317||92|
|10.||Sony A7R II||Full Frame||42.2||7952||5304||4K/30p||26.0||13.9||3434||98|
|11.||Sony A7 II||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
|12.||Sony A7S||Full Frame||12.0||4240||2832||1080/60p||23.9||13.2||3702||87|
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).
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.
|1.||Sony A7S II||2400||n||3.0 / 1229||tilting||n||1/8000s||5.0/s||n||Y|
|2.||Sony A9||3686||n||3.0 / 1440||tilting||Y||1/8000s||20.0/s||n||Y|
|3.||Sony A7 IV||3686||n||3.0 / 1037||swivel||Y||1/8000s||10.0/s||n||Y|
|4.||Sony A7S III||9440||n||3.0 / 1440||swivel||Y||1/8000s||10.0/s||n||Y|
|5.||Sony A9 II||3686||n||3.0 / 1440||tilting||Y||1/8000s||20.0/s||n||Y|
|6.||Sony A7R IV||5760||n||3.0 / 1440||tilting||Y||1/8000s||10.0/s||n||Y|
|7.||Sony A7 III||2359||n||3.0 / 922||tilting||Y||1/8000s||10.0/s||n||Y|
|8.||Sony A7R III||3686||n||3.0 / 1440||tilting||Y||1/8000s||10.0/s||n||Y|
|9.||Sony A99 II||2400||Y||3.0 / 1229||full-flex||n||1/8000s||12.0/s||n||Y|
|10.||Sony A7R II||2400||n||3.0 / 1229||tilting||n||1/8000s||5.0/s||n||Y|
|11.||Sony A7 II||2400||n||3.0 / 1230||tilting||n||1/8000s||5.0/s||n||Y|
|12.||Sony A7S||2400||n||3.0 / 921||tilting||n||1/8000s||5.0/s||n||n|
|Notes: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.|
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 information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, both cameras under consideration feature an electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).
Concerning the storage of imaging data, both the A7S II and the A9 write their files 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. The A9 supports UHS-II cards (on its first slot), while the A7S II can use UHS-I cards.
For some imaging applications, the extent to which a camera can communicate with its environment can be an important aspect in the camera decision process. The table below provides an overview of the connectivity of the Sony Alpha 7S II and Sony Alpha A9 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
Mic / Speaker
|1.||Sony A7S II||Y||stereo / mono||Y||Y||micro||2.0||Y||Y||-|
|2.||Sony A9||Y||stereo / mono||Y||Y||micro||2.0||Y||Y||Y|
|3.||Sony A7 IV||Y||stereo / mono||Y||Y||full||3.2||Y||-||Y|
|4.||Sony A7S III||Y||stereo / mono||Y||Y||full||3.2||Y||-||Y|
|5.||Sony A9 II||Y||stereo / mono||Y||Y||micro||3.1||Y||Y||Y|
|6.||Sony A7R IV||Y||stereo / mono||Y||Y||micro||3.1||Y||Y||Y|
|7.||Sony A7 III||Y||stereo / mono||Y||Y||micro||3.1||Y||Y||Y|
|8.||Sony A7R III||Y||stereo / mono||Y||Y||micro||3.1||Y||Y||Y|
|9.||Sony A99 II||Y||stereo / mono||Y||Y||micro||2.0||Y||Y||Y|
|10.||Sony A7R II||Y||stereo / mono||Y||Y||micro||2.0||Y||Y||-|
|11.||Sony A7 II||Y||stereo / mono||Y||Y||micro||2.0||Y||Y||-|
|12.||Sony A7S||Y||stereo / mono||Y||Y||micro||2.0||Y||Y||-|
Studio photographers will appreciate that the Sony A9 (unlike the A7S II) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Both the A7S II and the A9 have been discontinued, but can regularly be found used on ebay. The A7S II was replaced by the Sony A7S III, while the A9 was followed by the Sony A9 II. Further information on the features and operation of the A7S II and A9 can be found, respectively, in the Sony A7S II Manual (free pdf) or the online Sony A9 Manual.
So how do things add up? Which of the two cameras – the Sony A7S II or the Sony A9 – has the upper hand? Is one clearly better than the other? 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 live-view autofocus: Features on-sensor phase-detection for more confident 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.
- Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
- Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
- Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
- 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 (14 : 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. A professional wedding photographer will view the differences between cameras in a way that diverges from the perspective of a travel photog, and a person interested in cityscapes has distinct needs from a macro shooter. Hence, the decision which camera is best and worth buying is often a very personal one.
How about other alternatives? Do the specifications of the Sony A7S II and the Sony A9 place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera listing whether the two cameras rank among the cream of the crop.
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 shooting 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 ratings of the cameras as published by some of the major camera review sites (amateurphotographer [AP], cameralabs [CL], digitalcameraworld [DCW], dpreview [DPR], ephotozine [EPZ], photographyblog [PB]). As can be seen, the professional reviewers agree in many cases on the quality of different cameras, but sometimes their assessments diverge, reinforcing the earlier point that a camera decision is often a very personal choice.
|1.||Sony A7S II||5/5||+||..||..||4.5/5||5/5||Sep 2015||2,999||ebay.com|
|2.||Sony A9||5/5||+ +||4.8/5||89/100||5/5||5/5||Apr 2017||4,499||ebay.com|
|3.||Sony A7 IV||5/5||+ +||4.5/5||89/100||4.5/5||4.5/5||Oct 2021||2,499||amazon.com|
|4.||Sony A7S III||..||+ +||5/5||91/100||4.5/5||5/5||Jul 2020||3,499||amazon.com|
|5.||Sony A9 II||..||..||5/5||90/100||5/5||5/5||Oct 2019||4,499||amazon.com|
|6.||Sony A7R IV||5/5||+||4.5/5||91/100||4.5/5||5/5||Jul 2019||3,499||amazon.com|
|7.||Sony A7 III||..||+ +||4.5/5||89/100||5/5||5/5||Feb 2018||1,999||amazon.com|
|8.||Sony A7R III||..||+ +||4/5||90/100||4.5/5||5/5||Oct 2017||3,199||ebay.com|
|9.||Sony A99 II||..||..||4.5/5||85/100||4.5/5||4.5/5||Sep 2016||3,199||ebay.com|
|10.||Sony A7R II||5/5||+ +||5/5||90/100||5/5||5/5||Jun 2015||3,199||ebay.com|
|11.||Sony A7 II||5/5||+||4/5||82/100||4.5/5||5/5||Nov 2014||1,999||ebay.com|
|12.||Sony A7S||4/5||..||..||86/100||4.5/5||5/5||Apr 2014||2,499||ebay.com|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
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
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Specifications: Sony A7S II vs Sony A9
Below is a side-by-side comparison of the specs of the two cameras to facilitate a quick review of their differences and common features.
|Camera Model||Sony A7S II||Sony A9|
|Camera Type||Mirrorless system camera||Mirrorless system camera|
|Camera Lens||Sony E mount lenses||Sony E mount lenses|
|Launch Date||September 2015||April 2017|
|Launch Price||USD 2,999||USD 4,499|
|Sensor Specs||Sony A7S II||Sony A9|
|Sensor Technology||CMOS||Stacked BSI-CMOS|
|Sensor Format||Full Frame Sensor||Full Frame Sensor|
|Sensor Size||35.6 x 23.8 mm||35.6 x 23.8 mm|
|Sensor Area||847.28 mm2||847.28 mm2|
|Sensor Diagonal||42.8 mm||42.8 mm|
|Sensor Resolution||12 Megapixels||24 Megapixels|
|Image Resolution||4240 x 2832 pixels||6000 x 4000 pixels|
|Pixel Pitch||8.40 μm||5.94 μm|
|Pixel Density||1.42 MP/cm2||2.83 MP/cm2|
|Moiré control||Anti-Alias filter||Anti-Alias filter|
|Movie Capability||4K/30p Video||4K/30p Video|
|ISO Setting||100 - 102,400 ISO||100 - 51,200 ISO|
|ISO Boost||50 - 409,600 ISO||50 - 204,800 ISO|
|Image Processor||BIONZ X||BIONZ X|
|DXO Sensor Quality (score)||85||92|
|DXO Color Depth (bits)||23.6||24.9|
|DXO Dynamic Range (EV)||13.3||13.3|
|DXO Low Light (ISO)||2993||3517|
|Screen Specs||Sony A7S II||Sony A9|
|Viewfinder Type||Electronic viewfinder||Electronic viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||2400k dots||3686k dots|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||1229k dots||1440k dots|
|LCD Attachment||Tilting screen||Tilting screen|
|Touch Input||no Touchscreen||Touchscreen|
|Shooting Specs||Sony A7S II||Sony A9|
|Focus System||Contrast-detect AF||On-Sensor Phase-detect|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/8000s||1/8000s|
|Continuous Shooting||5 shutter flaps/s||20 shutter flaps/s|
|Shutter Life Expectancy||200 000 actuations||500 000 actuations|
|Electronic Shutter||YES||up to 1/32000s|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||no On-Board Flash||no On-Board Flash|
|Storage Medium||MS or SDXC cards||MS or SDXC cards|
|Single or Dual Card Slots||Single card slot||Dual card slots|
|UHS card support||UHS-I||Single UHS-II|
|Connectivity Specs||Sony A7S II||Sony A9|
|Studio Flash||no PC Sync||PC Sync socket|
|USB Connector||USB 2.0||USB 2.0|
|HDMI Port||micro HDMI||micro HDMI|
|Microphone Port||External MIC port||External MIC port|
|Headphone Socket||Headphone port||Headphone port|
|Wifi Support||Wifi built-in||Wifi built-in|
|Near-Field Communication||NFC built-in||NFC built-in|
|Bluetooth Support||no Bluetooth||Bluetooth built-in|
|Body Specs||Sony A7S II||Sony A9|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||370 shots per charge||650 shots per charge|
|In-Camera Charging||USB charging||USB charging|
127 x 96 x 60 mm
(5.0 x 3.8 x 2.4 in)
127 x 96 x 63 mm
(5.0 x 3.8 x 2.5 in)
|Camera Weight||627 g (22.1 oz)||673 g (23.7 oz)|
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