The Zhiyun Weebill-S Image Transmission Pro Kit is compatible with the Sony Alpha 6400, I personally use the a6400 as well. I mostly use the Sony 18-200mm, the only thing that doesn't work 100% for me is the focus/zoom control as the weight shifts too far forward when the lens is extended. I suspect you won't have any problems with a fixed focal length though, as there shouldn't be much weight shift.