Video is different from stills, in that a lot of times you are working with other camera ops where footage needs to be matched. And yes unlike a stills project, a videographer may get hired by a production company where they are looking to hire an owner/operator.
Pricing video is different than stills. I feel the big riff between old school videographers and the still photographers who are making the transition is the lack of understanding how video projects need to be priced. With video the videographer needs to rent the equipment to the client or production house. For example if I am asked to create ten employee head-shots (still photos) on a blank back drop. I am going to price my time, the licensing and the production costs. Maybe I’m able to bill for a roll of seamless paper. The established business practice is to provide a camera, lens, and proper lighting equipment.
With video the equipment list is much more extensive and can grow exponentially within a couple of script/directorial changes. So the standard practice pricing to film those ten employees changes and needs to incorporate pricing any equipment the project requires including the camera.
Yes there are videography jobs where the production company is looking to bring on a C300 and therefore are looking to hire an owner/operator for the work. One of the freelance assistants I use also works as a second wedding videographer, she just bought into Canon because it’s easier to match footage if the team is using the same camera or at least same manufacture. I have one friend who doesn’t even own a camera yet works(ed) on some very popular shows. Bringing up the idea if you invest in a c300 and then have a company/project that wants to use a Black Magic or FS700 why waste your money on camera bodies in the first place.
Back to the OP’s question: I really like that you are only renting I use that excuse when producers think I’ll show up with $20,000 of gear and only have to pay me a camera op’s rate. And yes I do believe we are sliding this way because still photographers making the transition without taking the time to learn some of the important business practices.
Personally I think it’s a great time to buy a used camera. People are selling in anticipation and I’ve heard people liking the a7r2 better for video over the a7s2. Craigslist’s where I’m at is full of A7r2s some I’ll bet haven’t been used more than ten times. imho I wouldn’t be buying a new camera today unless you need the receipt before 2018.
I think I was dreaming to think that the 3s would contain h265. Might the a7s3 contain 422 10bit too much of a guess to know?? 10bit 422 in the a7s might make slog usable and therefore something that an editor might sell the producer on, maybe??? But honestly I think where the A series accelerates people are not going to care if it’s any of the cameras in the A series. So the question is wait for an AF system that’s a bit better? That’s a question only your type of shooting/work can decide.