I had a shoot last week where we flew my Arri 35-3 on a steadicam and
used a Modulus video transmitter [like we have used many times].
Whenever the 35-3 turned on, we got a horrible picture...rolling & cutting video. When the camera stopped and the shutter parked, the picture
was fine. When we used the same Modulus on a Moviecam, it was fine.
I suspect that the Arri 35-3's motor is causing the video signals disruption.
Does anyone know if this is a common problem?
Jeff Barklage writes :
>I had a shoot last week where
we flew my Arri 35-3 on a steadicam and >used a Modulus
video transmitter [like we have used many times].
It's not common, but it does happen. It may be RF interference from the
motor, but it may also be that the Steadicam’ s video wiring is
adding to the problem.
Some older taps were very prone to this problem.
Try separate power supplies for the camera and tap and see if the problem
It may also be time to get your motor cleaned and tuned.
IA 600 DP
Jeff Barklage wrote :
>Whenever the 35-3 turned on,
we got a horrible picture...rolling & cutting >video.
Sounds like the motor was making a mess of the power. I had a similar
but probably not as bad problem flying my SR on my steadicam. I threw
a capacitor across the + & - of the power leads to the tap and that
helped tremendously but did not cure the problem completely.
My .02 is that it is a problem that involves motor interference interacting
with the high intensity steadicam monitors.
This was a fairly common problem with older Arri cameras.
The solution is to power the Modulus separately from the camera. It's
also a good idea to move the Modulus on the rig so that it is physically
as far from the camera motor as possible.
Jeff Barklage wrote :
> When the camera stopped and
the shutter parked, the picture was fine.
This may be a dumb question, but were you powering the tap from the camera,
or the same battery that powered the camera?
I've seen that cause the problems you describe.
Cinematographer - Gladstone Films
Cinematography Mailing List - East Coast List Administrator
Better off Broadcast (B.O.B.)
New York, U.S.A.
Steven asked this question [in response to my post regarding video assist
interference with a 35-3 on a Steadicam] :
>This may be a dumb question,
but were you powering the tap from the >camera, or the
same battery that powered the camera? I've seen that >cause
the problems you describe.
Yes, the Modulus and the CEI Color-V are all powered from the same 3-way
Fischer splitter box attached to the camera. I was assuming that a common
ground, between all 3 electrical components: camera, tap & transmitter,
would help matters.
What's weird is that the picture is beautiful while the camera is stopped,
but as soon as the motor spins, it goes bad.
I check to make sure the voltage drop wasn't the issue...it's not. So,
I am guessing that it is the motor's brushes?
I'll try bench testing with the camera off any mount and with separate
power supplies for the transmitter & body.