Sony a6400 hands-on review

Think you can’t afford an awesome camera? Then you haven’t seen Sony’s A6400

Artificial Intelligence gives the A6400 a huge leap forward in autofocus performance.
Artificial Intelligence gives the A6400 a huge leap forward in autofocus performance.
Artificial Intelligence gives the A6400 a huge leap forward in autofocus performance.


  • Great new autofocus system
  • Solid image quality across the board
  • Expanded ISO range up to 102,600
  • 180-degree flip screen
  • Very good value for the price


  • No in-body image stabilization
  • AF performance depends on lens used
  • Some frustrating user interface elements

After lavishing so much attention on full-frame mirrorless cameras for the past two years, Sony has finally found the time to look again to the smaller APS-C format. The recently introduced A6400 ($900, body only) receives many features trickling down from Sony’s full-frame line, despite being less than half the cost.

The A6400, as its name would suggest, falls in just underneath 2016’s A6500. Despite being lower-end, it benefits from being newer and offers many features — like a 180-degree flip screen and faster autofocus — not found on the A6500. Attending Sony’s A6400 launch event for the new camera, this left us with one primary question: Is it an unbeatable bargain, or too good to be true?

Same look, new tech

At 4.75 x 2.75 x 2.4 inches and weighing just under a pound at 14.3 ounces with battery and memory card loaded, the Sony A6400 looks and feels almost identical to the A6500. The one notable difference is the new LCD screen. While the A6500’s could rotate up and down, the A6400’s flips a full 180-degrees into “selfie” position. Aside from shooting selfies, this is also a helpful feature for vloggers. In a bit of a design flaw, you have to remove the viewfinder eyecup in order to get the screen to the full 180-degree position, but the offending bit of hardware slides easily on and off. We have to imagine these eyecups are going to end up in the same graveyard where all lost lens caps go.

For better or worse, the control scheme remains largely unchanged, including the minuscule movie record button that’s awkwardly wedged into the edge of the thumb rest. We’ve complained about this for years, but, like Sony’s menu systems, our squawks — and those of other reviewers — have fallen on deaf ears.

Sony a6400
David Elrich/Digital Trends

But what Sony lacks in design sensibility, it makes up for with raw technological power. One of our favorite features of Sony cameras is Eye-AF, where the camera focuses on your subject’s eye even as the person moves through the frame. This offers an incredible advantage for portraiture, and the system is reliable enough that it almost always gives consistent and predictable results.

The new A6400 has an improved version of this system called “Real-Time Eye AF” that not only tracks the eye, but the person as well, thanks to artificial intelligence. Better yet, it works automatically once you’ve enabled the system via the lovely menus (more on this in a bit). It also lets you choose which eye to focus on, or you can set it to automatic.

The company took this technology a step further with Real-Time Tracking, which uses similar algorithms and A.I. to recognize subjects and follow them (no eyes necessary). This is cool stuff and our brief use of the A6400 showed its potential.  (Note: an A9 firmware upgrade due in March gives that camera Real-Time Eye AF and Tracking while the A7R III and A7 III April firmware upgrades bestow Real-Time Eye AF for those full-frame cameras. Later this year Real-Time Eye AF for animals will be introduced for all of these cameras, thrilling pet lovers worldwide.)

Besides the new Real-Time features, the A6400 received a few other boosts compared to older Alpha series cameras — and one glaring omission. The hybrid autofocus system has been improved to 425 phase detect points combined with 425 contrast detect points, an improvement over the the more expensive A6500 ($1,200, body only) which had 425 points, but could only use contrast detection on 169 of them. The new system covers 84 percent of the image area, close to the 93 percent of the full-frame flagship A9.

The A6400’s autofocus is the fastest of any Sony yet, with a stated .02-second acquisition speed, a world’s best. (Sony seems to make hundredth-second improvements in autofocus with each new camera that comes out, and we’d be lying if we said we could always notice the difference; the A6400 certainly felt very fast, however). Battery life has also improved to 360 shots versus 310 for the A6500, although this is still far below the 700-plus rating of the new A7 III full-frame camera.

The A6400 receives many features from Sony’s full-frame cameras, despite being less than half the cost.

One point Sony emphasized in the reveal was that the A6400 would reach new heights in ISO performance for an APS-C camera. It uses a similar 24-megapixel sensor to the A6500, but native ISO range has been increased to 100-32,000, expandable to 102,400. That’s a full stop improvement over the A6500’s expanded max ISO of 51,200, but its native high of 25,600 is just a third of a stop behind the A6400.

Maximum mechanical shutter speed is 1/4000 second, 1/32,000 with the electronic shutter. Burst modes are unchanged from the A6500, topping out at 11 frames per second. That said, the A6500 has a much larger memory buffer that can hold a couple hundred images before slowing down; the A6400 can shoot just 99 JPEGs or 46 RAWs (according to the specifications) before hitting the limits of its buffer. Still, this is more than enough for the vast majority of shutterbugs, particularly those shopping in the $900 price range.

Videographers will be pleased with the oversampled 4K recording. For achieving higher dynamic range, the A6400 offers both S-Log and, a first for a Sony APS-C camera, Hybrid Log Gamma (HLG). You also get a microphone jack, but like the A6500, there’s no headphone jack. These are strong video features for a sub-$1,000 mirrorless camera, but there is one thing it lacks: in-body image stabilization. This is where the A6400 really can’t compete with the A6500, which uses excellent 5-axis internal stabilization. This could be a deal breaker for vloggers who otherwise may have flocked to the A6400 for its low cost and flip-up screen.

User experience

Alongside some 50 journalists and YouTubers at Sony’s San Diego headquarters, we got to try out a production sample of the A6400. Sony supplied three lenses with the camera: the 24mm f/1.8 ($1,099), the 18-135mm f/3.5-5.6 ($599), and the ultra-wide 10-18mm f/4 ($849). Of these, only the 10-18mm had optical stabilization.

Real-Time Eye autofocus and and Real-Time Tracking are major advancements.

One nice thing about these organized camera events is that we get a chance to test the camera in a variety of settings in a short amount of time, both indoors and out. Sony had arranged jugglers, basketball and volleyball players, musicians, and even Frisbee-catching pooches to model for us. As we were also testing the A9 with its new firmware update, this left us feeling pretty rushed, but we still got a good sense for the A6400’s capabilities.

First off, the Real-Time Eye AF and Tracking are major advancements. Rather than fumbling for controls during action, you can concentrate on your subject and let the camera do the heavy lifting. Sony had set custom controls and menus so the Real-Time features would engage with a half-press of the shutter button. This was great and it should be the default for the camera out of the box. We didn’t see an owner’s manual but we hope instructions for enabling the Real-Time technologies are easy to follow, because it’s a feature that even casual shooters will appreciate.

Low-light shooting was one of improvements Sony touted for the A6400. We did a series of images (tasting cups of tequila) in a dim restaurant up to ISO 102,400. Sure, the color shifted and there was plenty of noise, but it was impressive to see an APS-C sensor perform so well. It won’t replace full-frame, but it’s quite good. Videos shot in low light were also relatively noise free with solid color and little rolling shutter.

On the downside, things didn’t hold up so well when shooting outdoors in the rain. Even with Real-Time AF, the photos came out soft. Other photographers noticed the same thing and, guessing this was the fault of the lower-end lenses we were testing, many of us decided to swap in the G Master glass we had been provided with the A9. Lo and behold, image quality was far superior.

1080p, 60fps sample footage

This doesn’t exactly come as a shock, but it’s a reminder that even entry-level cameras can benefit greatly from high-end glass. It’s a bit of a shame, because most people in the $900 bracket are likely going to be working with the more affordable lens options, and those simply won’t reach the performance potential of the A6400. If you can afford to, you should skip the kit lens and save up for something better. Sure, it’ll cost you, but this has a huge payoff and makes the difference between a camera that is merely acceptable and one that is exceptional.

Bottom line

The Sony Alpha A6400 is a solid camera, especially considering its $900 starting price. We were very impressed with the new Real-Time autofocus technologies and can’t wait to see where Sony takes them in the future. We’ll have to wait until we have time to conduct a full review before offering a final verdict, and the lack of in-body image stabilization is certainly an issue for some potential buyers, but for now, we can safely say the A6400 shows a lot of promise, and no alternative immediately comes to mind that can best it at this price point.

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