Jim Hyslop Posted March 13, 2009 Share Posted March 13, 2009 Hi, I was 2nd AC on a short film a while back, and we shot a scene on location. One of the lights we used was a KinoFlo. Power was provided by a diesel trailer genny. When I watched the film, I noticed the Kino was flickering. Could that have been caused by the genny not generating exactly 60 Hz, or by the camera being slightly off-sync? Or would you have to see the shot to be able to comment? -- Jim Link to comment Share on other sites More sharing options...
Ryan Thomas Posted March 13, 2009 Share Posted March 13, 2009 (edited) Unless you were shooting some strange shutter, I'm just going to take a stab at it and say that the genny's voltage was a little off. That could be culprit with the flicker. You would just have to adjust the voltage on the genny while you measure it with a voltage meter to make it correct. Edited March 13, 2009 by Ryan Thomas Link to comment Share on other sites More sharing options...
JD Hartman Posted March 13, 2009 Share Posted March 13, 2009 Only the Kino seemed to be flickering? Could be a bad tube. If the generator voltage was low, light from any Tungsten fixtures would have looked a warm on the monitor. Flicker is caused by power frequency not voltage. Link to comment Share on other sites More sharing options...
Jim Hyslop Posted March 14, 2009 Author Share Posted March 14, 2009 (edited) I forgot to mention we were shooting on an Arri SR3, which has a fixed shutter. Yes, only the Kino was flickering - the tungsten lamps were fine. A couple of other factoids that may affect things: it was just above freezing, and we ran into problems with the battery later that day. Could the cold or a low battery voltage have affected the camera speed? Edited March 14, 2009 by Jim Hyslop Link to comment Share on other sites More sharing options...
JD Hartman Posted March 15, 2009 Share Posted March 15, 2009 In general florescent lights don't like the cold. Did it seem like the tubes took a while to reach full brightness. I can't comment on Kino's electronic ballasts, but most floro ballasts will have problems with low temperatures. Reliable operation at low temperature requires a different design. Link to comment Share on other sites More sharing options...
Premium Member Adrian Sierkowski Posted March 15, 2009 Premium Member Share Posted March 15, 2009 Arri SR3 has a variable shutter... If you hold down the "Phase" button on the camera you can be certain of where it was set. I would say perhaps cold on the floros and/or an older/bad tube. Link to comment Share on other sites More sharing options...
Jim Hyslop Posted March 17, 2009 Author Share Posted March 17, 2009 Arri SR3 has a variable shutter... If you hold down the "Phase" button on the camera you can be certain of where it was set. Oh. Good thing I was only 2nd AC :-) Thanks for the info. I've downloaded the manual but haven't had a chance to read through it yet. So, the consensus seems to be either a bad tube or the cold. Is there any kind of test we could have run before shooting? BTW, the flicker was fairly subtle - most audience members probably wouldn't notice it. Thanks for all the replies! Link to comment Share on other sites More sharing options...
Jamie Metzger Posted March 17, 2009 Share Posted March 17, 2009 [quote name='Jim Hyslop' post='278182' date='Mar 16 2009, 08:24 PM']Oh. Good thing I was only 2nd AC :-) Thanks for the info. I've downloaded the manual but haven't had a chance to read through it yet. So, the consensus seems to be either a bad tube or the cold. Is there any kind of test we could have run before shooting? BTW, the flicker was fairly subtle - most audience members probably wouldn't notice it. Thanks for all the replies![/quote] SR2 has a fixed shutter. There could be the possibility that the shutter was at a different degree, and it wasn't a safe angle. I know on the sr3 you can shoot 24/25/29.97, and if you were at 29.97, a kino would definitely flicker, as would HMI's. Too many variables though. Ballast, and the tube seem more reasonable. Link to comment Share on other sites More sharing options...
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