Mr. Macgregor Posted May 20, 2007 Share Posted May 20, 2007 Sooo. I am shooting film at 24 fps. In the back i have a rear projector displaying images shot in HD at 25fps ( i might easily resampled them to 24 fps anyway) but usually DLP even in PAL countries run at 59.94 fps. How can i achieve a flicker free image? i am lost. Link to comment Share on other sites More sharing options...
Premium Member Tony Brown Posted May 23, 2007 Premium Member Share Posted May 23, 2007 Test. Any sync sound? If not shoot the sequence using a phase sensor Link to comment Share on other sites More sharing options...
Mr. Macgregor Posted May 23, 2007 Author Share Posted May 23, 2007 No sound. What is a phase sensor? Link to comment Share on other sites More sharing options...
Premium Member John Sprung Posted June 4, 2007 Premium Member Share Posted June 4, 2007 Sooo. I am shooting film at 24 fps. In the back i have a rear projector displaying images shot in HD at 25fps ( i might easily resampled them to 24 fps anyway) but usually DLP even in PAL countries run at 59.94 fps. How can i achieve a flicker free image? i am lost. Definitely test. If you'll be shooting with a 180 degree shutter, then just running a mirror shutter camera empty and looking in the finder (provided it's a 180 degree mirror) will tell you a lot. The bad news is that DLP's are not all the same, and the results for one make and model aren't valid for another. This is because the pixels on the chip are either on or off, so to make a gray scale, they have to do something called duty cycle modulation. Basically that just means that they turn them on and off very rapidly, and by varying the number of clock periods on vs. off they get all the different brightnesses they need. But that's done off the actual display chip, and each display or projector make and model may do it differently. The good news is that most of them have very high clock rates, and their algorithms tend to spread the on's and off's around quite evenly. What may be a bigger problem is that single chip DLP's -- the ones with a color filter wheel -- can only put up one color at a time. Bottom line, test with the actual projector and the actual playback material. -- J.S. Link to comment Share on other sites More sharing options...
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