TV SYNC w/ PANAVISION "ELAINE"

[James Mann]

Hello Friends of Knowledge.

 

Am getting ready to shoot a film with Panavision's "ELAINE" (thanks to Panavision's generous donation thru the emerging filmmakers program - if you don't know about it, check it out).

 

Will need to sync up the camera to a CPU monitor (unfortunately not an LCD but rather one of those old school black-screen green-text monitors).

 

I was looking through the ASC book about the camera and it said (i think this is where I got this crazy idea from) that you can eliminate the flicker thru shutter control. I know that the camera has a variable shutter (from 50 - 200) and a variable speed (4fps to 50fps).

 

Our package does not come with a precision speed control (to punch in 29.97 and then phase out the bars) and the rest of the production doesn't really call for one so I am wondering: HOW would one go about eliminating TV/MONITOR flicker thru the use of the shutter.

 

Thanks.

 

James Mann

[Satsuki Murashige]

Some Panavision Elaines have an variable shutter. The control is on the back of the camera body. If you are in 60Hz land, you'd set the shutter to 144 degrees at 24fps to eliminate the scan lines on a CRT monitor. I don't know if the camera also has a phase control to move the scan line to the bottom of the frame or not. Just be aware that even though the camera may have a variable shutter control on the back of the camera body, the shutter itself may have been swapped out for a fixed shutter. I've seen this happen on a shoot with the Elaine before, so there's at least one camera body floating around with this problem.

[David Auner aac]

Hi James,

 

first of all 29.97 is for NTSC monitors so it doesn't apply to computer CRTs AFAIK. (If I am wrong here, correct me!) And I would check the back of the CRT in question for info on it's refresh rate, some really old monitors had really strange rates.

 

Cheers, Dave

[Charles MacDonald]

first of all 29.97 is for NTSC monitors so it doesn't apply to computer CRTs AFAIK. (If I am wrong here, correct me!) And I would check the back of the CRT in question for info on it's refresh rate, some really old monitors had really strange rates.

Actully, most monitors since about 1990 are "multisync" and so the refresh rate depends on the computer driving them. You may or may not be able to get this information from the video driver on the computer.

 

Recent units may show you the rate as part of the onscreen menu, the one I am using right now says it is running at at 60Hz, and that is probaly actually 60 and not 59.9

[David Auner aac]

Actully, most monitors since about 1990 are "multisync" and so the refresh rate depends on the computer driving them. You may or may not be able to get this information from the video driver on the computer.

 

Recent units may show you the rate as part of the onscreen menu, the one I am using right now says it is running at at 60Hz, and that is probaly actually 60 and not 59.9

 

Hi Charles,

 

the only problem is that the computer in question is really old (I think most black/green or orange Hercules driven machines are from the mid to late 80s. So my guess is that the monitor has only one refresh rate.

 

And IIRC its hard to look up the refresh rate on a DOS machine. You needed some kind of tool, like vesablabla.exe right? (in DOS times that would have been vesablab.exe :D)

 

And monitors that output the refresh rate their OSD came much later, I think not before the very late 90s. Maybe around 97?

 

Regards, Dave

[Charles MacDonald]

the only problem is that the computer in question is really old (I think most black/green or orange Hercules driven machines are from the mid to late 80s. So my guess is that the monitor has only one refresh rate.

OH YA, I rember those, sort of, the step after folks stoped using Commodore pet and Apple ][ machines.. I remeber those guys were in the 50- 60hz range, but have not a clue where you could find a reference to the exact speed.

 

Nasty though that comes to mind is to find a small engine repair place and see if they have an optical tachometer. Aim that at a corner of the screen and work the refresh out from that. (the gismo I am thinking of is aimed at a spot on a turning shaft and converts the flashes of light to a calculatated RPM of the shaft, (Actually Camera workshops mught have something like that also))

 

The one hopefull thing is that I do recall that the orange/yellow ones often had a longer glowing phosphor to reduce the apperance of flicker. and that may give you a bit of a break.

[Satsuki Murashige]

OH YA, I rember those, sort of, the step after folks stoped using Commodore pet and Apple ][ machines.. I remeber those guys were in the 50- 60hz range, but have not a clue where you could find a reference to the exact speed.

Maybe James could borrow an HVX camera, set the camera to 24P and adjust the shutter using the synchro scan function to find the correct shutter angle to use.