I have some rolls of Rollei BW infrared. Does anyone have any experience with this film they can share with me? I'm trying to read up on how to generally focus and expose for film, but im getting mixed messages since apprently this film is not as sensitive as other IR BW films. Some day I can focus without a red 25 filter, other say you have to and to use DOF to focus. Which I dont know how to do. I tried and I couldn't tell what I was doing. Needless to say, I am very confused.