Sony surprised attendees at IBC with the announcement of the α7S II mirrorless camera, the brand-new follow-up to the low-light wonder it first revealed on the stage at NAB 2014.

The α7S II records full-frame 4K UHD (3840×2160) video internally with full pixel readout and without pixel-binning, the company said, using the XAVC S codec running at up to 100 Mbps. (A Class 10 or higher SDXC memory card is required for XAVC S recording, and a UHS Class 3 memory card is required for 100 Mbps recording.) Full pixel read-out is also used in 24p and 30p HD modes, which provide approximately 5x oversampling. 1080p HD video can be recorded at up to 120 fps.

The 12.2 Mpixel 35mm full-frame sensor delivers 14 stops of dynamic range, according to Sony, with a standard ISO range of 100–102400 that can be expended to 50–409600. Dynamic range is optimized thanks to Sony's Bionz X image processor.

Picture profile settings include S-Gamut3.Cine/S-Log3 and S-Gamut3/S-Log3. Upgraded contrast-detecting autofocus offers 169 AF points, with autofocus performance working twice as fast as it did on the previous α7S II, Sony said.

And still photographers can rejoice — the camera will feature user-selectable compressed and uncompressed 14-bit raw still image capture, a feature that is being added to more cameras via firmware update, starting with the α7R II.

The α7S II is expected to ship in October for "about $3,000," Sony said.