Sony's video foray into prosumer 4K bears all the hallmarks of its 3D venture -- mismatching the desires of the potential buyers with its corporate needs. The new Handycam FDR-AX1 Ultra HD (aka Quad HD)-resolution camcorder seems to be designed to sell TVs to the few deep-pocketed consumers bemoaning the lack of high-resolution TV content and pros looking for cheap higher-resolution capture. But those are very different buyers and it seems to miss the boat on both. The $4,500 price tag and HDR-AX2000-based design of the Handycam FDR-AX1 are attractive to the latter group, but there are probably more quality shortcuts to do cheap 4K than those folks would like. On the flipside, the design and price are likely overkill squared for even the most enthusiastic video enthusiast.
On the outside, it's nearly identical to the AX2000 -- same lens, same features and controls, same jacks and connections. Inside, it's got a single 1/2.3-inch, 18-megapixel Exmor R sensor that outputs 3,840x2,160-pixel video. Based around the XAVC S codec, a more highly compressed (Long GOP) version of pro-friendly XAVC/H.264 Level 5.2, videos are encoded in an MP4 wrapper, which means they should be relatively widely supported. (The camcorder will ship with a full version of Sony's Vegas Pro 12 video editing software.) That said, it employs 4:2:0 color subsampling, and bit rate maxes out at 150Mbps at 60p or 100Mbps for 30p or 24p. In comparison, uncompressed 60p 4:2:0 video would require 5.6Gbps throughput (play with the bit-rate calculator). That compromise is necessary to keep the editing and playback bandwidth requirements within the constraints of well-equipped consumers. On the upside, you can record and encode standard HD at 50Mbps, a nice improvement over AVCHD. Also, the camcorder supports NTSC/PAL switching, so all the PAL equivalents of the frame rates are available.
In addition to the affluent hobbyist, Sony thinks the camcorder might appeal to wedding and indie videographers. But I can't see it as an optimal wedding-friendly camera. What you gain in resolution you'll probably lose in dynamic range because of that 4:2:0 limitation, which can be a real drawback for all that high-contrast, tonally challenging wedding work. Plus, its recommended minimum illumination level is 4 lux, which is higher than most of its HD competitors and may be limiting for some aspects of wedding shoots. A lot of its similarly priced HD competitors use three-chip systems, less crammed/larger-pixel sensors than the AX1's 18-megapixel 1/2.3-inch singleton, and they use 4:2:2 subsampling for better color. I can see its attractions for indie filmmakers, though I suspect many of these potential users would rather go 4K Cinema or go for interchangeable-lens options. Landscape and nature videos might be the best fit, as it's most likely to benefit from the increased detail resolvability the higher resolution facilitates.
To sustain the necessary write speeds, the camcorder incorporates two XQD slots. XQD cards are currently running about $200 for 32GB, at least for the current fast 168MBps models; the slower, cheaper ones, which I think would still work, seem to be unavailable. You can fit about an hour of highest-quality video on the bundled 32GB card, but the high cost of the media is another pain point. Sony plans to roll out a firmware update in spring 2014 to add AVCHD support (meh) and support for SD cards, at least for HD shooting.
Through some magic hand-waving, which I suspect is really just frame dropping, the AX1 can directly display 2160/60p on 4K Sony TVs; it will require a firmware update to support HDMI 2 in order to directly play 4K on other TVs. And I believe it can output clean -- but not uncompressed -- video via HDMI.
While there's some valid naysaying on the TV side about the necessity of 4K, it's much different on the capture side. If you're planning to edit video (or stills), you want to start with as much data as possible, and in theory downsampled QHD can be higher quality than direct-captured HD simply because your computer's got more power to downsample than a camcorder, and you can downsample after editing.
The AX1 feels like two different products squashed together. Price aside, a prosumer 4K camcorder should look and feel more like the VG900 and a cheap pro model should offer lower-compression options and damn the bandwidth, and perhaps even an option for recording to external media.
But maybe Sony has worked some magic within those constraints. We shall see when the Sony Handycam FDR-AX1 ships in in mid-October.