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BFD and Coherent video sender


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#1 Rich Cottrell

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Posted 25 March 2004 - 04:45 PM

I know Jim Bartell mentioned a few years ago that the Coherent video sender, because it works on the 900mhz range, has caused problems when used with a BFDs. (I just looked through the archives and i thik it was 2001 or 2002.)

I noticed that Coherent is having a good sale on their systems [from an ad on the top of this forum], and was thinking about them again; but i have a BFD and i will not be changing that.

So the question is, are any of you BFD users also using a Coherent [or other 900mhz] video sender?
And if you did get interference between the two, did you loose video or focus?
or did you loose both?

thanks,
rich
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#2 RonBaldwin

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Posted 28 March 2004 - 02:50 PM

I've also had alot of problems with the actor's wireless mics causing pain and confusion with my bfd (mostly pain). Sometimes moving in to an over, the motor would start stuttering/zipping all over the place. At first I thought the dp (he was pulling iris) was having a seizure, or it was an odd artistic choice...but a quick glance over to him revealed that he was indeed not moving the iris back and forth from 4 to 16 during the take. Bummer. I loath stopping a take because of an equipment issue -- especially when the equipment is owned and strapped to me!

I imagine that the Coherent will indeed cause problems, but call them up and get a loaner to try out. They've been cool about that in the past (I've never done it, but they've offered a few times). I am curious about the Coherent's proformance.

Ron B
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#3 Michael Stumpf

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Posted 28 March 2004 - 03:19 PM

Ron,

Did you check your batteries after that take?
I know, when my batteries get low, the first thing that happens is my motor starts to bounce all over the place and have a "seizure" like you stated.

I've NEVER had interference with any mics from any sound department with my BFD.

I fly a Modulus 3000 and find it works best at channels above 35.
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#4 Alec Jarnagin SOC

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Posted 29 March 2004 - 01:08 PM

I've NEVER had interference with any mics from any sound department with my BFD.

I fly a Modulus 3000 and find it works best at channels above 35.

I've been using a BFD since 1999 when they first came out. I, too, have never encountered interference from wireless mics. On a movie, awhile back, Jamie Silverstein and I were doing dueling Steadicams with two motors running each (focus and iris) as well as our transmitters in Time Square (can you say RF?) with both the talent on wireless mics - no problems anywhere.

As for the Modulus channels, I stick to the 20s and 30s. I have found that at 50 or above, you can get problems - this also depends on what channel your Bartech is set to. Since your iris unit was obviously set to a different channel than your focus, it is possible your Modulus was causing a problem with that unit. For extra safety, try keeping below channel 40 on your Modulus.

Otherwise, I'd have your unit checked out.
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#5 RonBaldwin

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Posted 02 April 2004 - 02:11 PM

I think Jim said to keep the modulus under channel 40 when using a bfd (which I do) and the battery was fine. I also tried different channels on the bfd, but it didn't help...as the actor walked towards me the bfd went nuts, visa/versa as he walked away (is my bfd gay?). I would have talked to the noise boys about why they hated me so much, but it was faster to simply add a preston motor and have the ac do the pull. Once my show's over I will send it in for a tune up/oil change, and perhaps some spooning from some bfd's in Jim's workshop.

I have to admit that I don't use it as often as some of you (only when doing exteriors so the dp can pull his own iris) but I do mount the reciever so I can see the red/green led...and it goes back and forth alot during use. Maybe that's normal, I don't know. I'm not bad-mouthing Jim's product, just telling a funny story where it bit me in the ass. My preston hasn't bit me in the ass yet, but the chunk missing from my wallet has left one cheek bigger than the other.

Ron
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