6
Figure 9 shows the color stabilization of the light after 5 minutes.
IMPORTANT NOTE ON BULB IGNITION / COOL DOWN:
Should you turn off the fresnel or should the power go out
(unplanned), you should not expect the fresnel to light again for
5 minutes or so. If you do turn it back on before the cool down
period is over, there is an enforcing timer in the ballast that
keeps it from coming on until it senses the bulb has cooled
down enough. It will retry every 2 minutes or so until it senses
the current necessary to ignite is in the proper range (bulb is
cool) and will then reignite. This type of bulb and system is
known as a
“
cold start
”
system or
“
not hot restart
”
(NHR). An
“
HMI
”
(Osram Trademark) or one of its
“
clones
”
is a hot restart type bulb and has a lesser life.
This is one major reason why the CDM 70 bulb life is so long as it is not a hot start (HMI) type
of bulb. This hot restart process is extremely stressful to the bulbs and the main reason that
HMI bulbs do not last much over 750 to 1000 hours.
Beam focusing
. On the back of the fresnel is a knob
for focusing the spotlight beam between a wide and
narrow beam. The knob simply controls a screw drive
which rolls the focus sled inside the fresnel back and
forth. You will find this to be one of the best features of
a fresnel and also the kind of control you typically won
’
t
find in a floodlight or other type open face light. The
ability to go between a wide or narrow beam and the
barndoors will allow many different kinds of effects.
Colored gels clipped to the barndoors make the effects
even more interesting. Effects such as a light streak on
the background behind a subject. In figure 10, you can
also see a handle on the back of the unit, this is to allow
easy positioning of angle of the fresnel while it is hot.
Angle adjustment using the yoke
. When you need to adjust the
angle of the fresnel, un-tighten the thumbscrew knob on the side of
the fresnel and using the handle (shown in figure 10) on the back of
the fresnel simply move into the position desired and retighten the
thumbscrew as shown in Figure 11.
Barndoors
.
The CL-MF0070
CDM 70 fresnel includes as
standard a barndoor unit which
fits into the accessory holder on
the front of the fresnel. The
barndoors come attached to the
fresnel out of the box. They are
Figure 12
–
Barndoor lock.
Figure 9
–
Color Stabilized
after 5 minutes.
Figure 11
–
Angle
adjustment thumbscrew.
Figure 10
–
The beam focus knob and
handle.
