nebraska focus racking
Posted 11 June 2015 - 09:27 AM
Posted 11 June 2015 - 10:40 AM
I don't think there is an iris rack though in the D.I. the colorist may have tried to pull a little bit of overexposed detail down once the focus shifted to the background, but I didn't really see a change.
The stretching laterally is an artifact of classic rear-anamorphic prime lenses. Early CinemaScope lenses had a problem where when the lens was focused to near minimum, the amount of optical squeezing was decreased to less than 2X, but in projection, with a constant 2X lateral stretch, those shots, mainly close-ups, looked fatter.
So Panavision solved the problem of "CinemaScope Mumps" but it meant that to keep to point of focus at a constant 2X horizontal squeeze, the out-of-focus areas would get more than a 2X squeeze, so they look skinny even after the image is stretched back out laterally by 2X. So when you do a focus rack, you see the amount of squeezing shift as a form of lens breathing. The only way to minimize it is to stop down the lens a lot to reduce the amount of frame that is out of focus.