Are still lenses really that hard to pull focus? How much more difficult would it be to pull focus with a Canon 24mm f/1.4 L on a 7D than with a Cooke S4 25mm T2.0 on a 7D-PL mount? If I were using a 24mm lens and an aperture of f/8, would I still need a follow focus for a handheld scene? I saw somewhere that the DP for Black Swan shot the subway scenes by himself on a 7D with a still lense. Is there any possible setup where the focus would not need to be adjusted during a handheld scene?