Sony A6400 vs A9
The Sony Alpha A6400 and the Sony Alpha A9 are two digital cameras that were officially introduced, respectively, in January 2019 and April 2017. Both the A6400 and the A9 are mirrorless interchangeable lens cameras that are based on an APS-C (A6400) and a full frame (A9) sensor. Both cameras offer a resolution of 24 megapixels.
Below is an overview of the main specs of the two cameras as a starting point for the comparison.
|Sony A6400||Sony A9|
|Mirrorless system camera||Mirrorless system camera|
|Sony E mount lenses||Sony E mount lenses|
|24 MP, APS-C Sensor||24 MP, Full Frame Sensor|
|4K/30p Video||4K/30p Video|
|ISO 100-32,000 (100 - 102,400)||ISO 100-51,200 (50 - 204,800)|
|Electronic viewfinder (2359k dots)||Electronic viewfinder (3686k dots)|
|3.0 LCD, 922k dots||3.0 LCD, 1440k dots|
|Tilting touchscreen||Tilting touchscreen|
|11 shutter flaps per second||20 shutter flaps per second|
|Lens stabilization only||In-body stabilization|
|not weather sealed||Weathersealed body|
|410 shots per battery charge||650 shots per battery charge|
|120 x 67 x 50 mm, 403 g||127 x 96 x 63 mm, 673 g|
Going beyond this snapshot of core features and characteristics, what are the differences between the Sony Alpha A6400 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.
An illustration of the physical size and weight of the Sony A6400 and the Sony A9 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 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 A9 is considerably larger (52 percent) than the Sony A6400. Moreover, the A9 is substantially heavier (67 percent) than the A6400. It is noteworthy in this context that the A9 is splash and dust-proof, while the A6400 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 compare the optics available for the two cameras in the Sony E-Mount Lens Catalog (A6400) and the Sony FE Lens Catalog (A9). 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 A6400 gets 410 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 adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. 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.
|Sony A6400||4.7 in||2.6 in||2.0 in||14.2 oz||410||n||Jan 2019||899|
|Sony A9||5.0 in||3.8 in||2.5 in||23.7 oz||650||Y||Apr 2017||4,499|
|Fujifilm X-T30||4.6 in||3.3 in||1.9 in||13.5 oz||380||n||Feb 2019||899|
|Nikon Z6||5.3 in||4.0 in||2.6 in||23.8 oz||310||Y||Aug 2018||1,999|
|Nikon D5300||4.9 in||3.9 in||3.0 in||16.9 oz||600||n||Oct 2013||799|
|Sony A9 II||5.1 in||3.8 in||3.0 in||23.9 oz||690||Y||Oct 2019||4,499|
|Sony A6100||4.7 in||2.6 in||2.3 in||14.0 oz||420||n||Aug 2019||749|
|Sony A7 III||5.0 in||3.8 in||2.9 in||22.9 oz||610||Y||Feb 2018||1,999|
|Sony A7R III||5.0 in||3.8 in||2.9 in||22.9 oz||650||Y||Oct 2017||3,199|
|Sony A6300||4.7 in||2.6 in||1.9 in||14.3 oz||400||Y||Feb 2016||999|
|Sony A7 II||5.0 in||3.8 in||2.4 in||21.1 oz||350||Y||Nov 2014||1,999|
|Sony A5100||4.3 in||2.5 in||1.4 in||10.0 oz||400||n||Aug 2014||549|
|Sony A6000||4.7 in||2.6 in||1.8 in||12.1 oz||360||n||Feb 2014||599|
|Sony A3000||5.0 in||3.6 in||3.3 in||14.5 oz||470||n||Aug 2013||329|
|Sony NEX-5R||4.4 in||2.3 in||1.5 in||9.7 oz||330||n||Aug 2012||749|
|Sony NEX-6||4.7 in||2.6 in||1.7 in||12.2 oz||360||n||Sep 2012||999|
|Sony NEX-7||4.7 in||2.6 in||1.7 in||14.1 oz||430||n||Aug 2011||1,349|
Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
(1) Number of images that can be taken on a full battery charge according to the CIPA-standard; (2) Official announcement.
Any camera decision will obviously take relative prices into account. 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 A6400 was launched at a markedly lower price (by 80 percent) than the A9, 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.
The size of the sensor inside a digital camera is one of the key determinants 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. 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 are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.
Of the two cameras under consideration, the Sony A6400 features an APS-C sensor and the Sony A9 a full frame sensor. The sensor area in the A9 is 131 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.
Even though the A9 has a larger sensor, both cameras offer the same resolution of 24 megapixels. This implies that the A9 has a lower pixel density and larger individual pixels (with a pixel pitch of 5.94μm versus 3.91μm for the A6400), which gives it a potential advantage in terms of light gathering capacity. It should, however, be noted that the A6400 is a somewhat more recent model (by 1 year and 8 months) than the A9, and its sensor might have benefitted from technological advances during this time that at least partly compensate for the smaller pixel size.
The Sony Alpha A6400 has a native sensitivity range from ISO 100 to ISO 32000, which can be extended to ISO 100-102400. 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.
For many cameras, data on sensor performance has been reported by DXO Mark. 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 A6400 (overall score 9 points higher), which will translate into better image quality. The advantage is based on 0.9 bits higher color depth, 0.3 EV of lower dynamic range, and 1.3 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.
|Sony A9||Full Frame||24.0||6000||4000||4K/30p||24.9||13.3||3517||92|
|Nikon Z6||Full Frame||24.3||6048||4024||4K/30p||25.3||14.3||3299||95|
|Sony A9 II||Full Frame||24.0||6000||4000||4K/30p||25.0||14.0||3434||93|
|Sony A7 III||Full Frame||24.0||6000||4000||4K/30p||25.0||14.7||3730||96|
|Sony A7R III||Full Frame||42.2||7952||5304||4K/30p||26.0||14.7||3523||100|
|Sony A7 II||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration have a sensor with sufficiently fast read-out times for 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 A6400 (3686k vs 2359k dots). The table below summarizes some of the other core capabilities of the Sony A6400 and Sony A9 in connection with corresponding information for a sample of similar cameras.
|Sony A9 II||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|Sony A7 III||2359||n||3.0||922||tilting||Y||1/8000s||10.0||n||Y|
|Sony A7R III||3686||n||3.0||1440||tilting||Y||1/8000s||10.0||n||Y|
|Sony A7 II||2400||n||3.0||1230||tilting||n||1/8000s||5.0||n||Y|
One difference between the cameras concerns the presence of an on-board flash. The A6400 has one, while the A9 does not. While the built-in flash of the A6400 is not very powerful, it can at times be useful as a fill-in light.The A6400 has an articulated LCD that can be turned to be front-facing. This characteristic will be appreciated by vloggers and photographers who are interested in snapping selfies. In contrast, the A9 does not have a selfie-screen.
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 A6400 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 A6400 only has one slot. The A9 supports UHS-II cards (on its first slot), while the A6400 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 A6400 and Sony Alpha A9 and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
|Sony A9 II||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|Sony A7 III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|Sony A7R III||Y||stereo||mono||Y||Y||micro||3.1||Y||Y||Y|
|Sony A7 II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
It is notable that the A9 has a headphone jack, which makes it possible to attach external headphones and monitor the quality of sound during the recording process. The A6400 lacks such a headphone port.
Studio photographers will appreciate that the Sony A9 (unlike the A6400) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.
The A6400 is a recent model that features in the current product line-up of Sony. In contrast, the A9 has been discontinued (but can be found pre-owned on eBay). As a replacement in the same line of cameras, the A9 was succeeded by the Sony A9 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 conclusions can be drawn? Is the Sony A6400 better than the Sony A9 or vice versa? The listing below highlights the relative strengths of the two models.
Advantages of the Sony Alpha A6400:
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- More compact: Is smaller (120x67mm vs 127x96mm) and thus needs less room in the bag.
- Less heavy: Is lighter (by 270g or 40 percent) and hence easier to carry around.
- Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
- More affordable: Was introduced into a lower priced category (80 percent cheaper at launch).
- More modern: Is somewhat more recent (announced 1 year and 8 months after the A9).
Reasons to prefer the Sony Alpha A9:
- Better image quality: Scores markedly higher (9 points) in the DXO overall evaluation.
- Better low-light sensitivity: Can shoot in dim conditions (1.3 stops ISO advantage).
- Better sound control: Has a headphone port that enables audio monitoring while recording.
- More detailed viewfinder: Has higher resolution electronic viewfinder (3686k vs 2359k dots).
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.70x).
- More detailed LCD: Has a higher resolution rear screen (1440k vs 922k dots).
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Faster burst: Shoots at higher frequency (20 vs 11 flaps/sec) to capture the decisive moment.
- Longer lasting: Gets more shots (650 versus 410) out of a single battery charge.
- Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
- Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
- 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 heavily discounted: Has been on the market for longer (launched in April 2017).
If the number of relative strengths (bullet points above) is taken as a guide, the A9 is the clear winner of the contest (15 : 6 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 A6400 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 technical specifications can provide a useful overview of the capabilities of different cameras, it remains incomplete and does no justice, for example, to the way the A6400 or the A9 perform in practice. 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 following table reports the overall ratings of the cameras as published by some of the major camera review sites (cameralabs, dpreview, ephotozine, imaging-resource, and photographyblog). 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.
|Sony A6400||+||85/100||4.5/5||..||4/5||Jan 2019||899|
|Sony A9||+ +||89/100||5/5||5/5||5/5||Apr 2017||4,499|
|Fujifilm X-T30||+ +||84/100||4.5/5||5/5||4.5/5||Feb 2019||899|
|Nikon Z6||..||..||4.5/5||4.5/5||5/5||Aug 2018||1,999|
|Nikon D5300||+ +||79/100||4.5/5||4.5/5||4.5/5||Oct 2013||799|
|Sony A9 II||..||90/100||5/5||..||5/5||Oct 2019||4,499|
|Sony A6100||..||82/100||4/5||..||5/5||Aug 2019||749|
|Sony A7 III||+ +||89/100||5/5||5/5||5/5||Feb 2018||1,999|
|Sony A7R III||+ +||90/100||4.5/5||5/5||5/5||Oct 2017||3,199|
|Sony A6300||+||85/100||5/5||5/5||5/5||Feb 2016||999|
|Sony A7 II||+||82/100||4.5/5||5/5||5/5||Nov 2014||1,999|
|Sony A5100||+||..||4.5/5||4.5/5||5/5||Aug 2014||549|
|Sony A6000||+||80/100||4.5/5||5/5||5/5||Feb 2014||599|
|Sony A3000||+||..||4/5||4.5/5||4/5||Aug 2013||329|
|Sony NEX-5R||..||..||4.5/5||..||4.5/5||Aug 2012||749|
|Sony NEX-6||+ +||78/100||4.5/5||5/5||4.5/5||Sep 2012||999|
|Sony NEX-7||+ +||81/100||4.5/5||5/5||5/5||Aug 2011||1,349|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
The review scores listed above should be treated with care, though. The assessments were made in relation to similar cameras of the same technological generation. 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. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.
Other camera comparisons
Did this review help to inform your camera decision process? If you would like to see a different side-by-side camera review, just use the search menu below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.
Specifications: Sony A6400 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 A6400||Sony A9|
|Camera Type||Mirrorless system camera||Mirrorless system camera|
|Camera Lens||Sony E mount lenses||Sony E mount lenses|
|Launch Date||January 2019||April 2017|
|Launch Price||USD 899||USD 4,499|
|Sensor Specs||Sony A6400||Sony A9|
|Sensor Format||APS-C Sensor||Full Frame Sensor|
|Sensor Size||23.5 x 15.6 mm||35.6 x 23.8 mm|
|Sensor Area||366.6 mm2||847.28 mm2|
|Sensor Diagonal||28.2 mm||42.8 mm|
|Sensor Resolution||24 Megapixels||24 Megapixels|
|Image Resolution||6000 x 4000 pixels||6000 x 4000 pixels|
|Pixel Pitch||3.91 μm||5.94 μm|
|Pixel Density||6.55 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 - 32,000 ISO||100 - 51,200 ISO|
|ISO Boost||100 - 102,400 ISO||50 - 204,800 ISO|
|Image Processor||BIONZ X||BIONZ X|
|DXO Sensor Quality (score)||83||92|
|DXO Color Depth (bits)||24||24.9|
|DXO Dynamic Range (EV)||13.6||13.3|
|DXO Low Light (ISO)||1431||3517|
|Screen Specs||Sony A6400||Sony A9|
|Viewfinder Type||Electronic viewfinder||Electronic viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||2359k dots||3686k dots|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||922k dots||1440k dots|
|LCD Attachment||Tilting screen||Tilting screen|
|Shooting Specs||Sony A6400||Sony A9|
|Focus System||On-Sensor Phase-detect||On-Sensor Phase-detect|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/4000s||1/8000s|
|Continuous Shooting||11 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||Lens stabilization only||In-body stabilization|
|Fill Flash||Build-in Flash||no On-Board Flash|
|Storage Medium||MS or SDXC cards||MS or SDXC cards|
|Second Storage Option||Single card slot||Dual card slots|
|UHS card support||UHS-I||Single UHS-II|
|Connectivity Specs||Sony A6400||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||no Headphone port||Headphone port|
|Wifi Support||Wifi built-in||Wifi built-in|
|Near-Field Communication||NFC built-in||NFC built-in|
|Bluetooth Support||Bluetooth built-in||Bluetooth built-in|
|Body Specs||Sony A6400||Sony A9|
|Environmental Sealing||not weather sealed||Weathersealed body|
|Battery Life (CIPA)||410 shots per charge||650 shots per charge|
|In-Camera Charging||USB charging||USB charging|
120 x 67 x 50 mm
(4.7 x 2.6 x 2.0 in)
127 x 96 x 63 mm
(5.0 x 3.8 x 2.5 in)
|Camera Weight||403 g (14.2 oz)||673 g (23.7 oz)|
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