Posted 03 July 2008 - 08:43 AM
Would adjusting the SHUTTER ANGLE do anything for me?
Shooting on a PANAFLEX 16. So our shutter is adjustable from 200 degrees to 50 degrees. There is some synch sound so adjusting the speed may not work.
Another option I suppose to make the key light flicker/pulsate somewhat. But it would seem a lot more motivated if the rest of the store had a sort of pulsating to it.
Posted 04 July 2008 - 07:20 PM
Squarewave ballasts will not flicker when dimmed.
Posted 06 July 2008 - 05:52 PM
Thank you, that is a good idea, but let's imagine that I am shooting in a supermarket with hundreds of overhead fluorescents fixtures. I have no way of dimming each unit individually and putting a dimmer somewhere in the store's power main doesn't seem feasible.
Is there something that I can do on the camera that would help me achieve the effect I am looking for?
Posted 06 July 2008 - 05:57 PM
It's easier to do this with a video camera where you can see the results immediately. Otherwise, shoot a test under any standard 60 Hz discharge lighting that uses magnetic ballasts. You might be able to just shoot a test at Panavision at different frame rates and shutter angles. Or if you don't have time for tests, borrow a Genesis camera there at Panavision during your prep day and play with the frame rates and take some notes.
Posted 06 July 2008 - 09:22 PM
Thanks for the timely reply.
I will be shooting a test tomorrow and will try out the 23 fps and 24 fps and a few different shutter angles.
I think that there may be some synch sound in the scene that I am trying to achieve this effect for so changing the fps may be a problem. But I'll talk to sound and see what he's got to say about the matter.
I'll post about the results...
Posted 06 July 2008 - 11:13 PM
Please do let us know about your results, I'm trying a similar effect and have been thinking about different ways of achieving it. I'm thinking more along the lines of a sporadic off-and-on flicker, but I'd also like to have some fluorescents continuously pulsating somewhere in the scene (a locker room).
Thanks for your question!
Posted 11 July 2008 - 08:58 AM
23 fps @ 190 degree
23 fps @ 170 degree
25 fps @ 190 degree
25 fps @ 170 degree
Found nothing. Though the rest of the test went pretty well...
Oh, the scientific method.
Posted 11 July 2008 - 01:21 PM
Shooting at 24 fps, you'd have 5 light pulses per frame, and there'd be no variation from frame to frame. By going just slightly off speed, you get a very slow pulsation. For instance, the TV rate 23.976 should give you a pulsation every 42 seconds. Going up to 25 fps gives you 24 light pulses in 5 frames, so your pulsation would happen every 5 frames. You could shoot sync at 25 like they do in the 50 Hz countries that way. For pulsation rates in between those, just pick a speed between 24 and 25 fps.
One more wild card to consider: Does your location have single phase or three phase power? All of the above is for single phase, which is what we all have at home. Large commercial and industrial buildings, though, can have three phase power. It looks to the camera like three different single phase systems equally spaced in time. In that case, only one third of your overhead lights would be on a gap between pulses at a time. Three phase gives you much more even power, which is really nice for big industrial motors, but exactly what you don't want for this shoot.