Household or office fluorescent lights will flicker at the line frequency, but
many fluorescents made for film or video use (such as most Kino-Flo’s) have
high-speed ballasts that allow use for high-speed shooting.
HMI’s, even those with electronic ballasts, may flicker. Due to the differences
in individual ballasts and lamps that affect the refresh rate and evenness of
illumination of a fixture, it will generally be necessary to test individual lamps
and ballasts to be sure.
Most un-dimmed LED lights designed for production use will not flicker, but
dimming will usually introduce flicker.
Most DC-powered lights will not flicker.There are several DC-powered xenon
lights manufactured by Luminys that will not flicker.
If you wish to use an unfamiliar light, it is best to test it before committing
to its use.
11
Lighting
10
Phantom Flex Manual
Phantom Flex Manual
don’t think about starting and stopping recording. It is not unusual to leave
the camera recording for a great deal of time – especially in a documentary
situation – before triggering the event.
For some, usually lower frame-rate shots, it is desirable to record
continuously for a time. With a CineMag this is possible. Direct recording
to a CineMag is the perfect solution for moderate frame-rate shooting
without any extra effort dedicated to trigger points or manually trimming
and saving shots. When recording to a CineMag directly, one starts and
stops the capture similarly to a traditional camera.
Lighting for high-speed cinematography can be a challenge. The two major
issues have been the intensity of light needed and flicker. With the high
sensitivity of the Phantom Flex the light needed is much less of an issue;
but many lighting sources that work perfectly for low frame-rate shooting
will cause flicker problems when used for high-speed work. In fact, you will
find that very many light sources that appear continuous to our eyes actually
flicker at a rate that we (and most cameras) don’t perceive. Any lighting unit
that flickers at the line frequency will generally be acceptable for use when
filmed at double the line frequency (120 or 100 fps, in North America and
Europe respectively.) Above these speeds special care needs to be taken
to avoid flicker
Small tungsten incandescent lights will flicker at double the line frequency
(i.e. at 120Hz in North America and 100Hz in Europe) as the tungsten filament
heats up cools during the different phases of the AC cycle. This affects both
practical lights as well as smaller, professional tungsten fixtures. Due to
their larger filaments, tungsten lamps of 2K watts or higher generally are
acceptable in 60Hz-land, and 5K watts or higher in the 50Hz world. If available,
tungsten lights in the 5K or 10K range are the ‘safest’ illumination for high-
speed work. Note that lights with multiple smaller lamps (such as nine-lights)
will generally flicker – what matters is the size of the individual lamps.
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