Speaking on the phone in chilly November from his houseboat on the River Thames, cinematographer Sean Bobbitt was far away — both physically and spiritually — from the hot, steamy countryside of Louisiana where he had spent summer 2012 shooting director Steve McQueen’s “12 Years a Slave” (pictured) in conditions that challenged cast, crew and equipment.

Striving for realism, McQueen insisted on filming in the locations where the story takes place, but it was a pure accident that the principal photography ended up taking place in July and August. “We were hoping it wouldn’t be the height of summer, but filmmaking being what it is, once the money was there we had no choice but to shoot in those two months,” Bobbitt says.

The timing turned out to be a blessing as well as a curse. “At the time we thought it was a shockingly bad period to shoot, but the truth is that the heat and climatic conditions add a whole other layer to the film,” he says. “When Chiwetel (Ejiofor) sweats, that’s not makeup, that’s real. Also, that heat and humidity make people move in a certain way. It’s an oppressive element that everyone has to deal with. For the slaves, it compounds the discomfort and inhumanity they have to deal with.”

Fortunately, the Louisiana-based crew was used to filming in such conditions. And Bobbitt shot on 35mm film using Arri cameras — “an extremely hardy and durable format, so there was never an issue. Film cameras are such ancient technology and they just churn on through.”

The only real problem was what Bobbitt calls the “biblical” thunderstorms that would periodically sweep over the plantations where the shooting was taking place. Every time lightning came within 10 miles, the generators had to be shut down for safety. On one occasion lightning burned out a crane’s circuit boards. Another time, some sound recording equipment got “fried.”

Throughout the process, Bobbitt and McQueen, who’ve collaborated on all three of the helmer’s movies, stuck to their belief in “the simplicity of the storytelling. If you find a strong frame that encompasses all the elements of the story and you let the actors get on with it, then you probably don’t need to do much else.”

Bobbitt considers this method “a reaction against a lot of conventional filmmaking techniques, where the film is created through the acquisition of a large number of shots, which are then put together in the edit to tell the story. Luckily, because of Steve’s art background that doesn’t make sense to him, so we don’t do it. We try to find the simplest and best way to tell the story on the day, on the location, with the actors — and stick to that.

“We choose locations very carefully, we discuss the possibilities of what might happen, but until the actors are on the set and do their thing, nothing is written in stone,” he adds. “The idea is to create a space for the actors to find their performance and then to capture that performance. Some days it’s easier than other days. You work at it, and you always get to it in the end.