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Performance
- 11fps burst shooting
- Improved buffer over A6300
- 360-shot battery life
To partner its advanced AF system, the Alpha A6400 can shoot at up to 11fps with both AF and AE. The buffer performance has been improved over the A6300's, with the A6400 able to shoot a total of 116 JPEG images compared to the A6300's 30, while for raw shooting, the capacity has been increased from 21 to 46 shots (although interestingly the A6500 has the upper hand here, capturing 200 JPEGs in a single burst at 11fps or 107 raw files). Should you want to shoot silently, you can do so at 8fps.
As far as metering goes, we found the A6400 to mostly be a reliable performer, with just an occasional bias towards underexposure; this is negligible though, and it's often by only around half or a third of a stop, so can easily be remedied with a touch of exposure compensation, or in post-capture raw processing.
The A6400's auto white balance system, meanwhile, does a good job of faithfully reproducing colors in a range of conditions, even impressing under typically problematic artificial sources.
As Sony has stuck with the same EVF as on both the A6300 and A6500 there are no surprises here, with a decent resolution and magnification for a camera at this price point. We did find that noise and lag increased in darker conditions, but this isn't unique to the A6400, and the image is still perfectly useable.
The battery hasn't been upgraded to the newer Z-series power packs found in the latest full-frame Alpha cameras, so battery life is a modest 360 shots if you're using the viewfinder regularly, while this can be stretched to 410 shots if you're happy to rely on the rear display. The Alpha A6400 is charged via USB, although a mains battery charger is sold separately.
Image quality
- Same sensor as the A6300 and A6500
- Image noise is well controlled
- Good-quality 4K video
The Alpha A6400 uses the same 24.2MP APS-C Exmor CMOS sensor as the A6300 and A6500. The A6400 gets the latest BIONZ X image processor though, which Sony believes delivers even better image quality.
We tested the A6400 with a variety of lenses, including the Sony E 18-135mm f/3.5-5.6 OSS, FE 24-70mm f/4 ZA OSS and FE 55mm f/1.8 ZA, and every combination delivered images rich in detail and with plenty of clarity.
JPEGs straight out of the camera look very impressive – sharpness is good, while the contrast is just about right too.
As we've seen with the A6300 and A6500, image noise is well controlled throughout the sensitivity range on the A6400, even if you opt for higher sensitivities such as ISO6400. If you're shooting JPEGs we'd recommend opting for the A6400's Low noise reduction setting, as the Normal setting can be a bit heavy handed.
Video quality (see below) is also excellent, with footage from the A6400 delivering plenty of detail, while motion is nice and smooth and audio quality is also very good. You'll want to think about a separate microphone if you're wanting the best sound possible, though – as with most cameras, wind noise can be an issue for the internal microphone on the A6400.
