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weak video assist signal-inline gain unit?


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#1 thomas-english

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Posted 01 March 2004 - 04:38 AM

pop an sr2 on... put a little t-bar bnc to split the signal from the dusty video assist (one to TX and one to sled). let AC screw the aperture down and hey presto--- dark monitor (panasonic lcd) real dark... then the film rolls and well your steadicaming blind. frantically try and turn the gain to maximum.. open up the assist aperture... no joy.. both wide. where are the mice?....

apart from battling with mild stupidness... am i also missing something?

can anybody recomend an inline 12v gain unit i could pop before the monitor? can anybody recomend a 12v signal booster for before the t-bar? im sure these are things that are built into the Marell etc monitors but i cant afford em so i reckon i should be able to get seperate units.............

i mean a high gain CRT monitor... is a normall CRT monitor with a good gain module before it?.................. i want a gain module........

do i? :ph34r:
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#2 Mitch Gross

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Posted 01 March 2004 - 09:57 AM

Video Accessory Corp. (vac-brick.com) makes video DAs that work off 12-32v power. They also make 12v only versions. They have about 30 variations in different sizes, some with multiple outputs (2,4 or 8) and options for individual gain control per output (less for your monitor, more for your transmitter, etc.), plus some simple economy models and some slimmed down units that you could squeeze into your junction box or electronics base. Try vac-brick.com or call 800-821-0426. Markertek.com is a distributor.
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#3 thomas-english

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Posted 01 March 2004 - 11:43 AM

wicked

found UK supplier.... ordering as i type

thanx
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#4 RobVanGelder

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Posted 01 March 2004 - 03:24 PM

I had the same experience with an SL, the other day. Not that it´s video-assist is so bad, but when they start shooting on 500ASA and push one stop, there is just not enough to work with......
So I quickly put together a +30Db video amplifier between the assist and the video-input of the sled ( I happened to have one print ready (?25))(not between the sled and the LCD because you will overload it with the framelinegenerator that is always 100%) and I could see at least where my actors were. But forget about other stuff, like stands or coffeecups in the background, no way you can see them in this case.

Rob van Gelder, Bangkok, Thailand
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#5 Ari Gertler

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Posted 01 March 2004 - 03:52 PM

I had a simillar problem recently with two Panavision 16mm camera that had a terible video assist. When we were shooting WFO, video assist gain boosted to the top, all detail was gone once the film was rolling, only basic shapes were visible. Even with Greg's fantastic TB-6 adjusted the best I could I still had difficulty. What is out there to help alieviate this problem besides more light?
Ari Gertler
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#6 thomas-english

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Posted 01 March 2004 - 05:40 PM

25 euro DistributionAmp? cool, is that bought in thailand though?

putting the amp before the sled... is that because a little signal gets lost in the sled? if i don have a frameline gen it should be fine? oooooo i see... is your frameline generator inside your sled?...... must be. so signal boost before and frameline generator or xcs level indicator or anything else that puts a signal on.

i guesse the problem is in the cheap ccd s ... my next sr2 shoot is on saturday and is at 120fps ... so i reckon the problem will be loads worse? seeing as the shutter shutting is half the dark problem.... hopefully one of these 120ukpound units mitch recomended me will do the trick

30db ey? thats loads.............
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#7 RobVanGelder

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Posted 01 March 2004 - 09:31 PM

No, the amp is bought and made in Holland, as a DIY board, with 1 input and 5 outputs and realy heats up the video signal.
That, said, it also heats up all the noise fron the camera motor so it doesn´t always work as expected.
I just looked back on my little DV recorder and it´s amazing that I managed to make the shots: in a blackened dockyard at night.


Rob van Gelder, Bangkok, Thailand
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#8 PatrickvanWeeren

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Posted 03 March 2004 - 12:31 PM

Dear everybody,

I read this post and thought about the next option?
Didn't anyone think of the consumer option on a DVcamera to switch it to NIGHT SHOT mode? Must be a way to make a video assist unit work with the same feature? (E.G. Lenses stopped down with ND polafilters, low light levels, high speed camera's )

Kind regards,


Patrick van Weeren
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#9 Mitch Gross

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Posted 03 March 2004 - 03:17 PM

Nightvision might work, but the beam splitter in many film cameras can cut the infrared frequencies which will kill any radiation getting to the appropriate sensor. So a nightshot camera may deliver a black image at that point.
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#10 RobVanGelder

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Posted 04 March 2004 - 10:17 AM

Not onlu the beamsplitter could make things worse, also the frame rate on most cameras goes down, in order to create a higher sensitivity. So You can have something like 15 FPSlooking ar a groundglass of a 24/25/30 fps camera
I´m not sure that is good and it will also introduce streaks and faded edges on moving objects. A least that is wat my very small Canon MV5 makes of it in low light or night mode.
But I will give it a try on of these days.

Rob van Gelder, Bangkok, Thailand
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#11 Kenny Brown SOC

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Posted 31 March 2004 - 02:17 AM

Hi there

I've had the same problems with weak video signals and found this thing online - anyone tried one of these or similar?

http://www.smarthome.com/77966.html

Kenny
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#12 thomas-english

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Posted 31 March 2004 - 12:23 PM

presently testing out

http://cgi.ebay.com/...&category=32808

but your one looks better.....
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#13 Benjamin Treplin

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Posted 31 March 2004 - 01:45 PM

Hi Kenny, Thomas,

try this one: VAC Video Distributor, Model VB/VDA-2
you can find it on following website in various shapes and functions:


http://www.vac-brick.com/

Benjamin
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#14 Frederic Chamberland

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Posted 01 April 2004 - 08:18 AM

Hi,

also try this, simple and efficient. And great service from Lentequip:

http://www.lentequip...eosplitter.html

Frederic Chamberland
steadicam@videotron.ca
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