Witchfinder General, 1968
Dir: Michael Reeves
The thing about any Vincent Price vehicle that I'm sure you've noticed is that if the ensemble around him is a bunch of cardboard cutouts than it just isn't going to work (think The House on Haunted Hill). But in this, the other actors, and especially Reeves' style, really helps with Price's hamminess, which is always evident ("I don't do accents."), but never overbearing.
Getting back to Reeves: if Robert Bresson were forced to direct a B-movie script about Matthew Hopkins, it might look like this.