The "s" stands for Sensitivity and Silence. The A7s is full-frame 12 Megapixel mirrorless stills camera, using the same body and design as the 24 Megapixel A7 and the 36 Megapixel A7r. The camera is also shooting 4K video through the clean HDMI output to the Atomos Shogun recorder in 8 bit 4:2:2. It takes Sony's FE mount lenses, Sony A SAL lenses and other A7 series accessories.
"Sony is producing more new and interesting cameras, in more categories, and with more new technology than the two market leaders combined. If leadership were judged by inventiveness they would already be #1". [Michael Reichmann]
The A7s is the low-light camera at the moment. The top ISO rating is only for emergency use only but I had shot nice portraits and city landscapes at 64000 ISDO. The other major benefit is the Silent shutter. Other brands has so called silent shooting mode which should be called more truthfully "Not so loud shutter" since the A7s is completely silent. This is a major benefit for concerts, events, weddings, funerals and any other situations where discrecy is needed.
Sony A7s reviews
Michael Reichmann Sony A7s First Impressions
EOSHD Sony A7s First Impressions Part 1
EOSHD Sony A7s First Impressions Part 2 and Conclusion
DxOMark Test and review for the camera Sony A7s
Den Lennie Hands on review
Phil Bloom Video review of the Sony A7s
B6H PhotoVideo Sony A7s
Best Mirrorless Camera Reviews Enjoy the light, love the dark - The Sony A7s Full Review
SONY: A7s video system guide (PDF File)
Phil Bloom A7s Seminar at B&H
The Lonely Bike Moments in Motion Atomos Shogun 4K Testvideo
Onyx Cinema Sony A7s vs GH4 vs C100 vs 5D Mark III (Part III) Low Light / High ISO
Stefan Czech Atomos Shogun meets Sony A7S in 4k & GH4 get 10bit 4:2:2 and more...
Stefan Czech Atomos Shogun Recorder 4K Videotest
Dave Dugdale Sony a7S Review as it Compares to the Panasonic GH4
Wolfcrow How to Expose, Monitor and Grade S-Log2 Footage on the Sony A7s
Michael The Mentor Sony A7S SLOG at 4K vs GH4 10 Bit 4K HDMI OUT Comparison Review
Tom Antos GH4 & Sony A7s Ultimate Camera Rig
Michael The Mentor Sony A7S SLOG at 4K vs GH4 10 Bit 4K HDMI OUT Comparison Revie
Phil Bloom Now I See
Ricky Spanish Low light video: Canon 6D vs Sony A7s
Erik Naso News update Shot With Sony Alpha A7s
The Photon Collective Atomos Shogun Review: Shooting in 4K with the Sony a7S
Ms High Defenition Sony A7s Accessories Mistakes! Metabones, Vello
Tips and Tricks
Gary Fong How To Configure Sony Autofocus (Moving Objects Or People)
SantaFe University How to Make a Short Film
Indy Mogul 7 Things to Know About Making Short Films!