Full Sony A7sIII FAQ and comparison with other cameras
Sony A7sIII Preorders:
Sony A7sIII in USA at Adorama (up to $400 off with lens). BHphoto. Amazon. FocusCamera.
Sony A7sIII in EU at Fotokoch. Calumet DE. WexUK. Park UK.
New Sony A7sIII accessories:
You will also have to preorder the world’s first CFexpress Type A cards at Adorama, BHphoto. Amazon.
And of course the new Sony MRW-G2 CFexpress Type A/SD Memory Card Reader at Adorama and BHphoto.
There is a useful Sony A7sIII FAQ page at Explora. They also have posted a special camera specs comparison post (Click here to read it all) .
And here you have two panel discussions on the new A7sIII: