The new Sony A7S created a lot of buzz with its outstanding low light / high ISO performance. Time for a more in depth analysis and a REAL WORLD comparison to the A7R, which was doing quite well at low light already.
As you might have studied already all kinds of technical specs, at this time I will not bother you with too many details anymore. Just the most relevant facts: Mirrorless E-Mount system camera with full frame sensor, 12 MP "only", ISO 100 ... 102400 (extended: 50...409600), 4K video (requires external recorder), FullHD 1080p with 50 MBit XAVC-S encoding on SDXC memory cards, up to 120 fps at 720p, 8 bit uncompressed output with 4:2:2 subsampling on HDMI, option for completely silent shooting.
Before we look at the video performance, let's start with some ISO samples (click on the images to see higher resolution versions).
ISO 100 (cropped, scaled), lens: SLR Magic HyperPrime CINE 50mm T0.95 @ T0.95: