May 19, 2016, 1:28pm
Does anyone have any advice when filming projectors?
I’ve been doing some tests with a Sony A7S filming a single chip (small) DLP projector, and haven’t managed to get an artefact free result.
No matter what framerate and shutter angle is used, I still get a vertical coloured line rolling down the ‘screen’ from top to bottom. Is this something to do with DLP vs LCD?
May 19, 2016, 1:34pm
no. it’s because of 1 Chip. get 3 Chip projector and this will solve your problem.
LCD is better, DLP do lots of hi frequency switching on and off of pixels, LCD stay on till updated per frame. Also are you outputting 60hz or 50? That will probably make a difference too.
May 19, 2016, 3:25pm
I get ok results by filming in 25fps with shutterspeed of 1/30s when filming single chip DLP.
Also it will depend on the number of segments in the colour wheel…
May 19, 2016, 7:37pm
sunep - presumably using 50hz projection?
Thanks for all the tips. I’m getting hold of some lcd pj to test
May 19, 2016, 9:20pm
@mrboni, actually no, also with 60Hz projections. but then again it also depend on the content on the screens, if there is a lot of flickering it is less suited for the camera to shoot.
Rule is simple, camera and beamer must be in sync: if beamer refresh rate is 60 hz, use 1/60sec or 1/30sec, if 50hz use 1/50sec or 1/25sec, some PAL cameras (my sony) has both options, and records band-free, stable image, some not (my other cam-Panasonic 4k PAL), and it also depends on the type of the shutter-I was not able to record projected image without flickering using Canon 650 DSLR at any settings…
May 31, 2016, 1:39pm
some graphics cards support “genlock”, which might be interesting to look into…
Genlock (generator locking) is a common technique where the video output of one source, or a specific reference signal from a signal generator, is used to synchronize other television picture sources together. The aim in video applications is to ensure the coincidence of signals in time at a combining or switching point. When video instruments are synchronized in this way, they are said to be generator-locked, or genlocked. Video signals generated and output by generator-locked instruments are ...
hope this helps.
you better just take an LCD projector instead of a DLP