The A6400 packs an all-new 24.2-megapixel Exmor APS-C sensor and next-gen BIONZ X image processor. It can handle high-speed continuous shooting at up to 11 fps with the mechanical shutter or 8 fps in silent shooting mode, both with continuous autofocus and auto-exposure tracking (you can capture up to 116 JPG frames or 46 RAW before the buffer fills up). That bests other recent APS-C cameras, most notably Fujifilm's pricier X-T3. As for low-light performance, you can shoot at up to 32,000 ISO or 102,400 expanded with less noise, Sony notes.

Sony's eye AF is the most popular feature on the A7 III series, and the A6400 takes that even farther. The advanced "real-time eye AF" deploys artificial intelligence to automatically detect a subjects' eyes in real-time, improving focus accuracy, speed and tracking. That tracking now includes animals' eyes, so you can keep Fluffy or Spot's eyes in focus, even at shallow depths-of-field.

The feature is now enabled by default (unless you shut it off), letting you either automatically or manually choose which eye to track. Real-time subject tracking, meanwhile, crunches depth, color, pattern and other spatial info to quickly and accurately follow your subject.

The A6400 can capture 4K at the sensor's full resolution, then oversample to deliver pin-sharp 4K footage, much as the A6500 does. You can also shoot 1080p at up to 120 fps. Sony promises that movie focusing is fast and stable thanks tot he hybrid AF tech, and the display, which completely flips around for vloggers, supports touch focus. There's a hybrid-log gamma feature to maximize image quality, along with a microphone port (but no headphone jack, unfortunately).

The new model lacks in-body stabilization, packs a single UHS-I card slot and boasts a relatively low-resolution 2.4 million dot XGA OLED viewfinder, unfortunately. It also uses an older NP-FW50 battery pack (with a 410 shot life), but at least Sony has introduced USB charging. However, it's priced at just $900, well below its existing A6500 and the X-T3, so the feature set is pretty solid for a mid-range mirrorless camera.

Along with the A6400, Sony also announced that it's bringing its advanced AI-powered eye- and subject-tracking features to its high-end full-frame A9, A7R and A7 III models. Those models will also get animal eye AF tracking, to take your cat (or lion) shots to the next level.

The A6400 name and specs suggests that the camera will slot between the A6300 and A6500, making it Sony's second-best APS-C mirrorless camera, numerically speaking. However, the A6500 is overdue to be replaced, so the speculation is that it will superceded by a newer model, possibly the A7000. If that's accurate, we should see that in the coming months. The A6400 arrives in February 2019 for $900 (body only), or $1,350 with the 18-135mm f/3.5-5.6 kits lens -- for more, check Sony's product page here.