First impressions

Sony's a6x00 series of cameras has always been a lineup that I've really wanted to like. After all, the a6000 is super affordable and super capable, the a6300 ups the ante with great autofocus and burst speeds, and the a6500 adds in-body stabilization to aid low-light photography and run-and-gun video shooting. But there have always been a few quirks in these cameras that kept me from really falling for them. And with the new a6400, Sony's made some serious changes to address some of my concerns - but not all of them.

Sony has combined Lock-On AF and Eye AF for one of the best AF implementations I've seen

Let's start with the biggest news on the a6400, which is its new 'Real-Time Tracking' autofocus system. While we already had 'Lock-On AF' and Eye AF in previous models, Sony has combined the two here for one of the very best autofocus implementations I've seen. But let's go back a bit and re-visit what subject tracking really is.

Subject tracking

Lots of people think subject tracking is just holding a point over your subject, and engaging continuous autofocus - but that's only part of it. True subject tracking means that the camera - not you - follows a subject around the viewfinder or rear screen, while continuously focusing on it - more to the point, it's tracking in more than one dimension. It's a revelation, and one that I've been trying to tell people about since I first discovered it on my D700 years ago. Here's what it looks like in Nikon's DSLRs today:

This is subject tracking. Initiating focus on a particular subject (or portion of a subject) and being able to recompose, freely, while the camera accurately maintains focus. It's an incredibly freeing way of shooting, allowing you to try more compositions without having to futz about with a joystick, touchpad AF, or a four way controller.

But Sony's gone one step further. While many manufacturers have had Eye Detection autofocus for a very long time, its usually a mode layered 'on top' of the regular system, and overrides your underlying settings. The Sony, though, seamlessly transitions from subject tracking to face detection to Eye AF and back again, easily tracking whichever subject you initially specified (even if they look away) without you having to worry about it. It's brilliant. (It's worth mentioning that this is now possible with Canon's EOS RP, but it's a little less sticky and reliable than Sony's - still, it's exciting to see more manufacturers moving this way.)

I don't have to dive into Sony's myriad list of AF options as situations change around me

This means that, in addition to not having to mess about with moving my AF area around very much, I also don't have to dive into Sony's myriad (and confusing) list of AF area options as situations change around me.

We used this video earlier in the review, but in case you skipped over it, you should really watch it. Not just for the adorable toddler, but because it's a great demonstration of how valuable this system will be for parents and families who may be looking at purchasing a digital camera to document their lives.

So that's the big news for me about the a6400. And it somewhat mitigates my big gripe with the camera, which concerns the ergonomics.

Where is my front dial?

The a6x00 series has never, for me, been a particularly engaging series of cameras camera to really use. They all have two dials, but you have to use your thumb for both, and the lower one is fiddly and imprecise. What this camera really, truly, desperately needs, is just a front dial under the shutter button. We've been asking for it for years, but the ergonomics of the a6400 remain pretty unchanged from the old NEX 5N from 2013.

And this isn't a huge deal for a lower-level offering like the a6000. But when Sony added countless features and capabilities into the a6300 and a6500, and thereafter upped the price into 'enthusiast' territory and basically ignored ergonomics, it left kind of a sour taste in my mouth. There grew a huge rift between the camera's capabilities and its user interface and ergonomics.

The wrap

I'm not trying to say that every camera needs to have the same ergonomics, controls, or design. Far from it, sometimes outside-the-box designs work really well. But, just for example, there are a number of cameras out there - like Panasonic's GX9 and Fujifilm's X-E3 - that come in at a similar size and overall design philosophy to Sony's a6x00 series and are just more pleasant to use, if less capable in some areas such as autofocus.

The Sony a6400 continues to offer great image quality in a compact package.
Cropped out-of-camera JPEG | ISO 3200 | 1/100 sec | F1.8 | Zeiss 24mm F1.8

So I guess what I'm trying to say is this - Sony, you've proven just how much technological prowess you have. Despite the relatively modest price of the a6400, this autofocus system is absolutely amazing (and I'm really looking forward to trying it out on the final version 5.0 firmware for the flagship a9).

But I'd like to take a breath here and get back to basics. Photography is a hobby, a profession, a lifelong passion for many folks. There is no doubt that it's incredibly important for a camera to enable the user to 'get the shot', which of course includes accurate focus, and as a point-and-shoot camera the a6400 is damn-near flawless. But it's also important for the photographer to really connect with and enjoy using the camera they've chosen to create that shot in the first place.