Sony A7S III vs A9 II
The Sony Alpha 7S III and the Sony Alpha A9 II are two professional cameras that were revealed to the public, respectively, in July 2020 and October 2019. Both the A7S III and the A9 II are mirrorless interchangeable lens cameras that are equipped with a full frame sensor. The A7S III has a resolution of 12 megapixels, whereas the A9 II 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 III and the Sony Alpha A9 II? 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.
An illustration of the physical size and weight of the Sony A7S III and the Sony A9 II is provided in the side-by-side display below. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All width, height and depth measures are rounded to the nearest millimeter.
If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7S III and the Sony A9 II are of equal size. However, the A9 II is slightly lighter (3 percent) than the A7S III. 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.
The battery packs of both cameras can be charged via USB, which can be very convenient when travelling.
The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. If you want to switch the focus of the display and review another camera pair, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.
|1.||Sony A7S III||127 mm||97 mm||81 mm||699 g||600||Y||Jul 2020||3,499|
|2.||Sony A9 II||129 mm||96 mm||76 mm||678 g||690||Y||Oct 2019||4,499|
|3.||Canon R5||138 mm||98 mm||88 mm||738 g||320||Y||Jul 2020||3,899|
|4.||Sony A1||129 mm||97 mm||81 mm||737 g||530||Y||Jan 2021||6,499|
|5.||Sony A7C||124 mm||71 mm||60 mm||509 g||740||Y||Sep 2020||1,799|
|6.||Sony A7R IV||129 mm||96 mm||78 mm||665 g||670||Y||Jul 2019||3,499|
|7.||Sony A7 III||127 mm||96 mm||74 mm||650 g||610||Y||Feb 2018||1,999|
|8.||Sony A7R III||127 mm||96 mm||74 mm||650 g||650||Y||Oct 2017||3,199|
|9.||Sony A9||127 mm||96 mm||63 mm||673 g||650||Y||Apr 2017||4,499|
|10.||Sony A7R II||127 mm||96 mm||60 mm||625 g||290||Y||Jun 2015||3,199|
|11.||Sony A7S II||127 mm||96 mm||60 mm||627 g||370||Y||Sep 2015||2,999|
|12.||Sony A7 II||127 mm||96 mm||60 mm||599 g||350||Y||Nov 2014||1,999|
|13.||Sony A99||147 mm||111 mm||78 mm||812 g||500||Y||Sep 2012||2,799|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
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 A7S III was launched at a somewhat lower price (by 22 percent) than the A9 II, which makes it more attractive for photographers on a tight budget. 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.
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 II offers a higher resolution of 24 megapixels, compared with 12 MP of the A7S III. This megapixels advantage translates into a 42 percent gain in linear resolution. On the other hand, these sensor specs imply that the A9 II 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 III). Moreover, it should be noted, that the A7S III is a somewhat more recent model (by 9 months) than the A9 II, and its sensor might have benefitted from technological advances during this time that further enhance the light gathering capacity of individual pixels.
The resolution advantage of the Sony A9 II implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the A9 II 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 III 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 II has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.
The Sony Alpha 7S III has a native sensitivity range from ISO 80 to ISO 102400, which can be extended to ISO 40-409600. The corresponding ISO settings for the Sony Alpha A9 II are ISO 100 to ISO 51200, with the possibility to increase the ISO range to 50-204800.
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 consideration, the A9 II has a markedly higher DXO score than the A7S III (overall score 7 points higher), which will translate into better image quality. The advantage is based on 1.3 bits higher color depth, 0.1 EV in additional dynamic range, and 0.4 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.
| DXO |
|1.||Sony A7S III||Full Frame||12.0||4240||2832||4K/120p||23.7||13.9||2520||86|
|2.||Sony A9 II||Full Frame||24.0||6000||4000||4K/30p||25.0||14.0||3434||93|
|3.||Canon R5||Full Frame||44.8||8192||5464||8k/30p||25.3||14.6||3042||95|
|4.||Sony A1||Full Frame||49.8||8640||5760||8k/30p||..||..||..||..|
|5.||Sony A7C||Full Frame||24.0||6000||4000||4K/30p||25.0||14.7||3407||95|
|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 A9||Full Frame||24.0||6000||4000||4K/30p||24.9||13.3||3517||92|
|10.||Sony A7R II||Full Frame||42.2||7952||5304||4K/30p||26.0||13.9||3434||98|
|11.||Sony A7S II||Full Frame||12.0||4240||2832||4K/30p||23.6||13.3||2993||85|
|12.||Sony A7 II||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
|13.||Sony A99||Full Frame||24.0||6000||4000||1080/60p||25.0||14.0||1555||89|
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, but the A7S III provides a higher frame rate than the A9 II. It can shoot video footage at 4K/120p, while the A9 II is limited to 4K/30p.
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 III offers a substantially higher resolution than the one in the A9 II (9440k vs 3686k dots). The table below summarizes some of the other core capabilities of the Sony A7S III and Sony A9 II in connection with corresponding information for a sample of similar cameras.
|1.||Sony A7S III||9440||n||3.0||1440||swivel||Y||1/8000s||10.0||n||Y|
|2.||Sony A9 II||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|6.||Sony A7R IV||5760||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|7.||Sony A7 III||2359||n||3.0||922||tilting||Y||1/8000s||10.0||n||Y|
|8.||Sony A7R III||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|10.||Sony A7R II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
|11.||Sony A7S II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
|12.||Sony A7 II||2400||n||3.0||1230||tilting||n||1/8000s||5.0||n||Y|
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).
The Sony A9 II has an intervalometer built-in. This enables the photographer to capture time lapse sequences, such as flower blooming, a sunset or moon rise, without purchasing an external camera trigger and related software.
The A7S III writes its imaging data to CFexpress or SDXC cards, while the A9 II uses SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. Moreover, both the A7S III and the A9 II support UHS-II cards, which provide for Ultra High Speed data transfer of up to 312 MB/s, on both slots.
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 III and Sony Alpha A9 II and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|1.||Sony A7S III||Y||stereo||mono||Y||Y||full||3.2||Y||-||Y|
|2.||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|
|10.||Sony A7R II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|11.||Sony A7S II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|12.||Sony A7 II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
Studio photographers will appreciate that the Sony A9 II (unlike the A7S III) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
Both the A7S III and the A9 II are recent models that are part of the current product line-up. The A9 II replaced the earlier Sony A9, while the A7S III followed on from the Sony A7S II. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official Sony website.
So what is the bottom line? Is there a clear favorite between the Sony A7S III and the Sony A9 II? Which camera is better? The listing below highlights the relative strengths of the two models.
Reasons to prefer the Sony Alpha 7S III:
- Better video: Provides higher movie framerates (4K/120p versus 4K/30p).
- More detailed viewfinder: Has higher resolution electronic viewfinder (9440k vs 3686k dots).
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.91x vs 0.78x).
- More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- Faster data transfer: Supports a more advanced USB protocol (3.2 vs 3.1).
- More solid recording: Has a full-sized HDMI port for a sturdy connection to an external recorder.
- More affordable: Was introduced into a lower priced segment (22 percent cheaper at launch).
- More modern: Is somewhat more recent (announced 9 months after the A9 II).
Advantages of the Sony Alpha A9 II:
- 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 low-light sensitivity: Can shoot in dim conditions (0.4 stops ISO advantage).
- Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- Longer lasting: Gets more shots (690 versus 600) out of a single battery charge.
- Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
- Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
- More heavily discounted: Has been on the market for longer (launched in October 2019).
If the number of relative strengths (bullet points above) is taken as a guide, the A9 II comes out slightly ahead of the A7S III (10 : 9 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. 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 III and the Sony A9 II 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 technical specifications can provide a useful overview of the capabilities of different cameras, it remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the A7S III or the A9 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 hands-on reviews by experts are important. The adjacent summary-table relays the overall verdicts of several of the most popular camera review sites (amateurphotographer [AP], cameralabs [CL], 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 III||..||+ +||91/100||4.5/5||5/5||Jul 2020||3,499|
|2.||Sony A9 II||..||..||90/100||5/5||5/5||Oct 2019||4,499|
|3.||Canon R5||4.5/5||..||91/100||4.5/5||4.5/5||Jul 2020||3,899|
|4.||Sony A1||..||..||..||..||..||Jan 2021||6,499|
|5.||Sony A7C||3.5/5||..||86/100||4/5||4/5||Sep 2020||1,799|
|6.||Sony A7R IV||5/5||+||91/100||4.5/5||5/5||Jul 2019||3,499|
|7.||Sony A7 III||..||+ +||89/100||5/5||5/5||Feb 2018||1,999|
|8.||Sony A7R III||..||+ +||90/100||4.5/5||5/5||Oct 2017||3,199|
|9.||Sony A9||5/5||+ +||89/100||5/5||5/5||Apr 2017||4,499|
|10.||Sony A7R II||5/5||+ +||90/100||5/5||5/5||Jun 2015||3,199|
|11.||Sony A7S II||5/5||+||..||4.5/5||5/5||Sep 2015||2,999|
|12.||Sony A7 II||5/5||+||82/100||4.5/5||5/5||Nov 2014||1,999|
|13.||Sony A99||5/5||..||84/100||4.5/5||4.5/5||Sep 2012||2,799|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
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 rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.
Other camera comparisons
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Specifications: Sony A7S III vs Sony A9 II
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 III||Sony A9 II|
|Camera Type||Mirrorless system camera||Mirrorless system camera|
|Camera Lens||Sony E mount lenses||Sony E mount lenses|
|Launch Date||July 2020||October 2019|
|Launch Price||USD 3,499||USD 4,499|
|Sensor Specs||Sony A7S III||Sony A9 II|
|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/120p Video||4K/30p Video|
|ISO Setting||80 - 102,400 ISO||100 - 51,200 ISO|
|ISO Boost||40 - 409,600 ISO||50 - 204,800 ISO|
|Image Processor||BIONZ XR||BIONZ X|
|DXO Sensor Quality (score)||86||93|
|DXO Color Depth (bits)||23.7||25.0|
|DXO Dynamic Range (EV)||13.9||14.0|
|DXO Low Light (ISO)||2520||3434|
|Screen Specs||Sony A7S III||Sony A9 II|
|Viewfinder Type||Electronic viewfinder||Electronic viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||9440k dots||3686k dots|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||1440k dots||1440k dots|
|LCD Attachment||Swivel screen||Tilting screen|
|Shooting Specs||Sony A7S III||Sony A9 II|
|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||10 shutter flaps/s||10 shutter flaps/s|
|Shutter Life Expectancy||200 000 actuations||500 000 actuations|
|Electronic Shutter||YES||up to 1/32000s|
|Time-Lapse Photography||no Intervalometer||Intervalometer built-in|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||no On-Board Flash||no On-Board Flash|
|Storage Medium||CFexpress or SDXC cards||SDXC cards|
|Second Storage Option||Dual card slots||Dual card slots|
|UHS card support||Dual UHS-II||Dual UHS-II|
|Connectivity Specs||Sony A7S III||Sony A9 II|
|Studio Flash||no PC Sync||PC Sync socket|
|USB Connector||USB 3.2||USB 3.1|
|HDMI Port||full 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||no NFC||NFC built-in|
|Bluetooth Support||Bluetooth built-in||Bluetooth built-in|
|Body Specs||Sony A7S III||Sony A9 II|
|Environmental Sealing||Weathersealed body||Weathersealed body|
|Battery Life (CIPA)||600 shots per charge||690 shots per charge|
|In-Camera Charging||USB charging||USB charging|
127 x 97 x 81 mm
(5.0 x 3.8 x 3.2 in)
129 x 96 x 76 mm
(5.1 x 3.8 x 3.0 in)
|Camera Weight||699 g (24.7 oz)||678 g (23.9 oz)|
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