In those days Newsrooms in TV stations/networks were just a bunch of desks for reporters, with phones and teletype machines. There's usually just one big camera, which is usually turned on just for the evening news. They were not turned on during the lunch hour when Kennedy was shot. the CBS camera took something like 20 minutes to get warmed up to shoot Cronkite. It was similar at NBC.
This was the world's first attempt at round-the-clock event reporting, it was a template of what has evolved over decades into CNN, Fox News and MSNBC today.
Many of the reporters who worked in Dallas that weekend had become well known big time journalists, many of them are still around.
The big tv cameras didn't have zoom lenses. They have a bunch of lenses in front and the operator had to rotate a big dial to get the right lens with the suitable focal length to shoot something. The camera used by NBC affiliate to televise the Oswald transfer was like that. The operator started with wide angle, and as Oswald stepped toward the vehicle the director instructed the cameraman to switch to close up. There was a brief blank on the NBC screen as the lens was switched, we got a brief close up of Oswald and then bang. If that cameraman wasn't fast enough, the shot might not had been televised.