Archived posting to the Leica Users Group, 1999/03/29
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I wrote: >> >> The ffd for Arriflex is 52.00 mm - that is the optical depth. Cameras >> are set so that the image is in focus 0.015 mm into the film, to allow >> for the thickness of the three layers. >> Martin Howard replied >Wouldn't the depth-of-focus (not depth-of-field) take care of that, even >for large apertures? 0.015mm sounds to me like it should be well within >the depth-of-focus range... > Surely depth of focus and depth of field are inseparable. If you make use of the tolerance in one, you lose it in the other. Remember also that the 35 mm sound movie format is a little smaller than half-frame, so the c-of-c is smaller than full frame. The ffd has to be set to something - so why not set it to the estimated position of the middle sensitive layer? High end movie cameras are made to be adjustable to very tight tolerances. Imagine shooting at 24 frames per second (and well above) with registration pins, and doing it almost silently. Regards, Malcolm Singapore PS My original post was WRONG. The ffd for the M is not 27.35 mm - it appears that there was a typo in the information sent to me by Leica. Aplogies to all for the duff info. I hope that this post makes sense. Yesterday's shoot ended at 10.30 am today and I am feeling dizzy from lack of sleep. Thank goodness I can't afford a car here - it forces me to travel by taxi.