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  1. #11
    Helen B's Avatar
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    Quote Originally Posted by David H. Bebbington
    I am doing a project where I photograph flowers in the studio with narrow depth of field. As I could not switch my 600-joule flash heads down far enough for an aperture of f2.8 and photofloods would be far too hot for flowers, I got two daylight bulbs which are rated at 6400 Kelvin, consume 45W and are supposed to emit as much light as regular 225W bulbs. Having reminded myself what a mired is, I did some calculations and figure that an 81A filter will give correct color rendering (possibly an 81B or 81C might look more pleasing). I have just shot some tests and am awaiting the results. The fluorescent lamps are pleasant to work with, they're even cooler than the modeling lights on my flash.

    Regards,

    David
    An 81B (+27 mireds or reciprocal megakelvins, MKˉ¹) certainly seems about right to change a CCT of 6400 kelvins to 5500 kelvins. A KR3 (+ 30 MKˉ¹) would also be close. Are you using reversal film or neg film?

    Best,
    Helen

  2. #12
    Lee L's Avatar
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    Nov 2004
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    Quote Originally Posted by Nick Zentena
    B&W has or at least had a document on filters. In the back of it is a little diagram for figure out temperture filters.
    Here, and 7.3 Mb: http://www.schneideroptics.com/filte...dbook_Full.pdf

    Lee

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