What's new and how it compares

Sony's a6400 looks almost identical to the previous a6300 on the outside, but with a fair number of refinements within. So while this doesn't address our qualms with the a6x00 series' controls and ergonomics, it does at least make the a6400 the nicest camera to use in the lineup so far.

Key takeaways:

  • New Bionz X processor (related to that in the professional a9) allows for better autofocus and faster bootup times among other benefits
  • Autofocus enhancements can change the way you shoot for the better
  • Interval shooting is now a menu item, not an added app
  • Customizable 'My Menu,' enhanced button customization and a 'help' option for every menu function is great for less experienced users

The processor

The a6400's Bionz X processor is not the exact same chip as in the professional-level a9, but it is related. While the highlight of the processor's new capabilities is the new Real-Time Tracking option, we've also noticed that overall operation is snappier than the a6300 and a6500, and boot-up times are noticeably quicker as well.

During extended video recording, the camera didn't get nearly as hot as previous models

Another enhancement, though, is the removal of the 30-minute video record time limit on the a6400. While this isn't strictly related to the processor, we did notice after extended video recording that the camera didn't get anywhere near as hot as previous models, and this is likely due to processing enhancements. In other words, we wouldn't guarantee that the a6400 will never overheat, but it certainly seems less prone to it than its predecessors.

Autofocus enhancements

Sony has long incorporated subject tracking in their E-mount cameras, and up until now, it was referred to as Lock-On AF. Of particular note is that Eye AF, which intelligently identifies the nearest eye of a human subject to focus on, was a separate function, and had to be assigned to a separate button press. Not so with the new 'Real-Time Tracking' system.

Sony's Real Time Tracking autofocus is seriously impressive.

The big story here is that, not only is Real-Time Tracking's behavior 'stickier' than Lock-On AF, but now, the camera will seamlessly transition from subject tracking, to face tracking, to Eye AF, and all the way back again, and it's possible with just a half-press of the shutter button.

With Real-Time Tracking, you can place an AF area over a face (or even just generally: a human subject) to start tracking a face or eye, or place the AF area over anything else to tell the camera to track that. Essentially, you never have to change your autofocus settings once you adjust to this way of working. While Canon has a similar implementation in its newer mirrorless cameras with Pupil Detection, few other autofocus systems work in this manner. Often, you will need to either enable or disable eye detection manually, because it will override all other autofocus settings.

So, the system looks promising indeed, and we'll take a closer look at how it performs later on in the review process.

Interval shooting

The a6400 gains built-in interval shooting, a function that had to be added as an 'app' or was completely absent from previous models. It's a robust implementation, even giving you control over autofocus sensitivity, as well as whether or not you want to use a silent electronic shutter.

Usability enhancements

As we hinted at earlier, the a6400 comes with a bevy of usability enhancements compared to the older a6300 and a6500 models, but they're mostly software based - our previous concerns about the a6x00 series' handling remain, thanks to the limited updates to the a6400's physical controls. But we'll discuss the controls in more depth later in the review.

The new interface for button customization makes it quicker and easier to get the functions you want mapped to the buttons of your choosing.

For now, we're pleased to see that the screen (which flips up 180° ) is touch sensitive. Although it's still not as responsive as many competitors' implementations, it does allow for easier AF area placement, touchpad AF with your eye to the finder and zooming in playback. You still cannot interact with either the main menu or function menu with it.

Sony has also updated the menus to their latest implementation, which does a better job of bundling settings together in a sensible fashion and includes colored tabs and headings as well. This was present on the more expensive a6500, but not on lower-priced models. There's also a new customizable 'My Menu' tab that you can populate with your most-used items.

Button customization menus have a little mockup of the camera to make the assignment of custom buttons quicker, since it allows you to visualize and check how you've got the camera set up right then and there. It's worth noting that this is rapidly becoming industry-standard practice, so it's nice to see on the a6400.

Sony's menus have come a long way between the a6300 and a6400.

Lastly, and this is nit-picky, but we noticed that the menus no longer look as though they were designed for a 3:2 aspect ratio and stretched to fill the 16:9 ratio of the a6400 screen. This was an oversight on the a6300, and always irked me just a little bit. Plus, the updated color tabs and headings really do go a long way to keep you from getting too lost in the menus, though it's bound to still happen occasionally.

Compared to...

Sony a6400 Sony a6300 Fujifilm X-T30 Canon M50
(body only)
$900 $1000 $899 $779

Pixel Count

24 MP 24 MP 26 MP 24 MP
Image stabilization In-lens only In-lens only In-lens only In-lens only
Maximum shutter speed 1/4000 1/4000 1/4000 1/4000
Sync speed 1/160 1/160 1/180 1/200
Cont. frame rate (with AF-C) 11 fps 11 fps 20 fps (30 fps w/1.25x crop) 7.4 fps
Viewfinder magnification 0.71x 0.71x 0.62x Unspecified
Viewfinder resolution 2.36M dots 2.36M dots 2.36M dots 2.36M dots
Rear screen res 921k dots 921k dots 1.04M dots 1.04M dots
Rear screen type Tilting touchscreen Tilting Tilting touchscreen Fully-artic touchscreen
4K video res UHD/30p UHD/30p UHD/30p UHD/24p
4K video crop 1x (24p)
1.22x (30p)
1x (24p)
1.22x (30p)
1x (full width) 1.56x
4K shutter rate (approx) 40ms (24p)
31ms (30p)
40ms (24p)
31ms (30p)
23ms 36ms
1080 video 120p 120p

120p 60p
Connectivity BT + Wi-Fi + NFC Wi-Fi + NFC BT + Wi-Fi BT + Wi-Fi
Battery life (CIPA) 410 400 380 235
Dimensions 120 x 67 x 60 mm (4.72 x 2.64 x 2.36") 120 x 67 x 49 mm (4.72 x 2.64 x 1.93") 118 x 83 x 47 mm (4.65 x 3.27 x 1.85") 116 x 88 x 59 mm (4.57 x 3.46 x 2.32")
Weight 403 g (14.2 oz) 404 g (14.3 oz) 383 g (13.5 oz) 390 g (13.8 oz)

If anything, this table highlights just how similar these cameras are on a spec-basis. But, of course, specs don't tell you everything, and the cameras differ significantly in terms of control and design philosophy. The a6x00 twins offer dual control dials, but you use only your thumb to operate them, which requires you to break / modify your grip to switch between them.

The Fujifilm is of course retro-inspired and gives you classic exposure controls with dedicated dials as well as dual clickable control dials for your thumb and index finger, and the less enthusiast-focused EOS M50 is the most basic of the bunch with a single dial, but with the best screen mechanism here for vlogging (without an external display, you cannot easily vlog on the X-T30). Of course, plenty of people will prefer a standard tilting design for stills-only shooting.