Sony announces full-frame Alpha A7s with 4K video output

It wouldn't be NAB without a major 4K announcement from Sony, and that's exactly what we've got here. The company introduced the Alpha A7s at its Las Vegas press event today, bringing 4K video to the popular full-frame mirrorless camera line. The "s" in the new camera's name stands for sensitivity, and to that end it supports an ISO range of 50 to 409,600. The 12.2-megapixel full-frame sensor limits downscaling with 3,840 x 2,160 (QFHD) 4K video, ultimately resulting in higher quality footage. While you can store 1080p video internally, you'll need to use an external recorder to capture 4K video, which the camera outputs with 4:2:2 color sampling via HDMI.

Update: A 4K video shot on the Alpha A7s is also included after the break.

You can store XAVC S-format video with a class 10 or higher SDXC card. When in 1080p mode, you can also opt to shoot with APS-C cropping, while 120 fps capture is supported when you jump down to 720p. The A7s can snap still images, of course, but it really shines when it comes to capturing 4K and HD video. The camera supports S-Log2 gamma, expanding the dynamic range to 1300 percent, resulting in reduced shadow and highlight clipping.

Physically, the A7s looks identical to its Alpha siblings, with a solid design and feel. It also sports WiFi and NFC, for wireless transfers to a smartphone or tablet. Also, like the other Alpha 7 cams, the A7s includes a Multi Interface Shoe, so you can add in Sony's XLR mic adapter kit, the XLR-K1M. Pricing has not yet been announced, but Sony executives say to expect the camera in stores this summer, just a few months after Panasonic's GH4. Check it out in our video below.

Sarah Silbert contributed to this report.