One of The Criterion Collection's short docs on The Innocents (1961), Between Horror, Fear, and Beauty features short interviews with editor Jim Clark, the script supervisor and cinematographer Freddie Francis. The limitations of this are clear: The director (passed away in 1995) and writers (one passed away in 1984) are absent, so there's not much insight about the story, though Clark notes at the end that there's much open to interpretation. Clark and Francis would be in a good position to talk about the filmmaking itself (there is, after all, no film without cinematography or editing). But the clips of Francis are so brief that ironically, Criterion's other featurette John Bailey on Freddie Francis is more informative.
That said, drawing on their recollections, Clark and the script supervisor reflect on some interesting tidbits on the production. While the most interesting analysis of the cinematography is in John Bailey on Freddie Francis, Between Horror, Fear, and Beauty reflects on what drew the storytellers to the project and how shooting on set created some claustrophobia in what is otherwise a large setting. The actors are all absent but there's recollections on how Martin Stephens and Pamela Franklin approached the project (they note Stephens was the professional; he would have to be). Some interest here, but make sure to check out the other doc too.