Fredrik Backar FSF Posted February 28, 2004 Share Posted February 28, 2004 Shooting music video using lots of 50fps and 75 fps shots. What are the safe speeds for kinos and divas?? Many thanks in advance!! Link to comment Share on other sites More sharing options...
Premium Member David Mullen ASC Posted February 28, 2004 Premium Member Share Posted February 28, 2004 Most speeds should be safe -- they use high-frequency ballasts so the pulse rate is very high, like 1000 times a second (I think.) Link to comment Share on other sites More sharing options...
Fredrik Backar FSF Posted February 28, 2004 Author Share Posted February 28, 2004 Thank you David! Link to comment Share on other sites More sharing options...
Jason Mann Posted February 29, 2004 Share Posted February 29, 2004 Be careful with them color-wise... we just used them on a shoot and their color temp was all over the place. Could be a bad set of tubes, but we had two Divas and lots of spares and they were all pretty unreliable. just a cautionary tale.... Link to comment Share on other sites More sharing options...
Premium Member Phil Rhodes Posted February 29, 2004 Premium Member Share Posted February 29, 2004 Hi, Fluorescent tube systems almost unavoidably change colour if you dim them, so if the calibration is off on your dimmable ballast you may find they range between purple (high voltage, high frequency, not enough tube current to keep the heaters warm or excite the mercury, generally when dimmed) to yellow (All the energy going through the mercury discharge and phosphor, none through the other rare gases, usually when at full whack.) Phil Link to comment Share on other sites More sharing options...
Jason Mann Posted March 1, 2004 Share Posted March 1, 2004 so is there any way to beat this tendency with the divas? b/c i love the size and dimmability of them, and i think they'd be nice little lights otherwise... thanks! Link to comment Share on other sites More sharing options...
Premium Member Phil Rhodes Posted March 1, 2004 Premium Member Share Posted March 1, 2004 Hi, No, not until someone builds a cold-cathode light. Cold cathodes dim more evenly, because they don't really react any differently when you pump enough energy through their electrodes to warm them up as they do when they're cold. They're not quite as efficient as fluorescents and they suffer slightly from a "thermometer effect" with certain ballasts, in that they can illuminate from one end then work along if you dim them enough. I'm not quite sure why nobody's done this. I have a prototype miniature cold-cathode softlight, but I'm not exactly in a position to make a market leader out of it - Arri? Kino? Anyone? Phil Link to comment Share on other sites More sharing options...
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