DDF4220HDV Picodome
®
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Notes for the Use of Fluorescent Light Sources (Fluorescent Lamps):
With fluorescent light sources (e.g. fluorescent lamps), typical 50/60 Hz video flickering
and fluorescent colour roll may occur in the video image (see below).
If you notice any of these effects in the video image, disable the WDR mode or select the
AE Preset “Fluorescent”.
When selecting the AE Preset “Fluorescent”, the Wide Dynamic Range (WDR) mode is
automatically disabled.
A manual reactivation of the WDR mode in conjunction with the AE Preset “Fluorescent”
is not recommended.
For more information about the WDR mode, see section “
50/60 Hz Video Flickering
Typical 50/60 Hz video flickering (“strobe effect”) may be caused by a significant fre
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quency mismatch between the vertical frame rate of the camera and the flicker fre
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quency of alternating current (AC) powered fluorescent light sources (e.g. fluorescent
lamps).
Example:
When using the camera in NTSC standard (30/60 fps) and with fluorescent light sourc
-
es, video flickering will occur in countries where the AC power frequency is 50 Hz, which
drastically differs from the NTSC video capture standard frequency of 59.94 Hz.
Fluorescent Colour Roll
The phenomenon “fluorescent colour roll” may be caused by a minor frequency mis
-
match between the vertical frame rate of the camera and the flicker frequency of alter
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nating current (AC) powered fluorescent light sources (e.g. fluorescent lamps).
Example:
Colour roll will occur when using the camera in NTSC standard (30/60 fps) and with
fluorescent light sources which are operated at a mains frequency of 60 Hz. Here the
mains frequency slightly differs from the NTSC video capture standard frequency of
59.94 Hz.
The reason for the periodically occurring colour fluctuations is that the colour tempera
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ture (spectral characteristics) of the fluorescent light source changes within each AC
power cycle (each zero crossing of the alternating voltage) which results in brightness
variations (illumination level changes).
Frequency mismatch normally does not occur when the PAL standard (25/50 fps) is
used in conjunction with 50 Hz AC power.
