Agreed on everything. That gorgeous oner on the beach:
"Another complicated scene to shoot was the long take, using a horizontal camera move, when Cleo walks from a beach into the sea to save the children from drowning.
“The first challenge was to find an inland beach facing northwest in Tabasco where we were shooting,” explains Cuarón. “It also had to be a beach that had waves that were a specular and that was controllable in terms of people swimming. We had to build a pier so that the Technocrane would always be at the same level with the water and sand.
“The sweet spot for the light was 5:30pm to 6pm. I wanted to have six takes in the can before the sun disappeared to make sure that we had it. The day before we shot, there was a tropical storm that weakened the structure of the pier. The crane kept on derailing, not even reaching the moment where Cleo gets into the water. Rebuilding the pier and coming back again later was too expensive and unfeasible. We were able to achieve just one take. I said to my producers that I would have to live with the shot. I thought it was not so good. But, eventually, when I was in the cutting room I was like, ‘Wow. This is great!’”
There's also an article in next month's AC magazine.
For the light, seemed to me like all available light really which seems to be what it was most of time they were outdoors really. The Alexa 65 shines on this, it wouldn't look nearly as good in color though. B&W can really make a lot of things that are boring in color really interesting. Not to deny the fact that Cuaron's work here is immaculate. Here's another conversation with Chivo: