Jump to content


Photo

On-screen Plasma TV's...


  • Please log in to reply
9 replies to this topic

#1 Christian Vandervort

Christian Vandervort
  • Basic Members
  • PipPip
  • 10 posts
  • Student
  • Los Angeles

Posted 22 July 2006 - 12:37 AM

I'm a student preparing to shoot a 24p project with a Sony F900 starting 7/27, and there is a scene in which two characters watch an episode of "I Love Lucy". Is the Plasma TV we have for the scene going to cause any flicker or other undesirable effect if I just shoot it? (i was recently told that it wouldn't)

I would appreciate any advice

Thanks ahead of time

Edited by cvander, 22 July 2006 - 12:39 AM.

  • 0

#2 Jim Murdoch

Jim Murdoch
  • Guests

Posted 22 July 2006 - 02:18 AM

I'm a student preparing to shoot a 24p project with a Sony F900 starting 7/27, and there is a scene in which two characters watch an episode of "I Love Lucy". Is the Plasma TV we have for the scene going to cause any flicker or other undesirable effect if I just shoot it? (i was recently told that it wouldn't)

I would appreciate any advice

Thanks ahead of time

It depends on the model. There's no particular reason a plasma screen needs to have its rows of pixels scanned in any particular order, and some manufacturers deliberately scramble the order to minimize flicker. Unfortunately, some others seem to do it more like a traditional CRT scan and you do get strobing effects.

The only way to find out is to shoot a test using a handycam or similar. If at all possible, use an LCD TV instead, they produce zero flicker.
  • 0

#3 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19769 posts
  • Cinematographer
  • Los Angeles

Posted 22 July 2006 - 11:43 AM

I would think that from a Plasma screen what you're more likely to see is a hertz pulse, more like HMI flicker than a roll bar from a CRT screen -- in other words, if this is a 60 Hz power, probably the optimal shutter speed is around 1/60th. But since this is a pro video camera, you can just use the clear-scan (ECS) function to remove the visible pulsing in the monitor.
  • 0

#4 Christian Vandervort

Christian Vandervort
  • Basic Members
  • PipPip
  • 10 posts
  • Student
  • Los Angeles

Posted 22 July 2006 - 12:43 PM

It depends on the model. There's no particular reason a plasma screen needs to have its rows of pixels scanned in any particular order, and some manufacturers deliberately scramble the order to minimize flicker. Unfortunately, some others seem to do it more like a traditional CRT scan and you do get strobing effects.

The only way to find out is to shoot a test using a handycam or similar. If at all possible, use an LCD TV instead, they produce zero flicker.


Well at one point I shot this TV successfully with a Canon XL2/ PS Technic Adapter at 24 p... is that any indication? (sorry I forgot to include this previously)
  • 0

#5 Jim Murdoch

Jim Murdoch
  • Guests

Posted 23 July 2006 - 03:38 AM

Well at one point I shot this TV successfully with a Canon XL2/ PS Technic Adapter at 24 p... is that any indication? (sorry I forgot to include this previously)

That should be OK then. Incidentally, the P&S adaptor doesn't really make any difference for test purposes, you can just point the camcorder directly at the screen. The "shutter angle" should ideally be "180 degrees" in other words 20.8833333333333333 milliseconds! But again, this will depend on the model
  • 0

#6 Jim Murdoch

Jim Murdoch
  • Guests

Posted 23 July 2006 - 03:50 AM

I would think that from a Plasma screen what you're more likely to see is a hertz pulse, more like HMI flicker than a roll bar from a CRT screen -- in other words, if this is a 60 Hz power, probably the optimal shutter speed is around 1/60th. But since this is a pro video camera, you can just use the clear-scan (ECS) function to remove the visible pulsing in the monitor.


The first plasmas I ever saw were completely strobe-free, like an LCD. I don't know why the manufacturers changed their designs, but some of the later models do produce a roll bar like a CRT screen, although not as intense. After giving somebody what turned out to be the wrong advice, my only advice now is "Test!" or use an LCD if there is any choice in the matter. In any event, LCDs come up really well on film, are much lighter, and getting cheaper by the hour.

BUT! Don't use any sort of polarizing filter with an LCD as you may not get any picture at all! (As many a bright young advertising dude has found when he came up with the bright idea of using an LCD screen mounted on its side as an animated advertising billboard. If your potential customer is wearing Polaroid sunglasses, he don't see n'owt!) B)
  • 0

#7 Bruce Greene

Bruce Greene
  • Basic Members
  • PipPipPipPip
  • 493 posts
  • Cinematographer
  • Los Angeles

Posted 31 July 2006 - 01:12 AM

I'm a student preparing to shoot a 24p project with a Sony F900 starting 7/27, and there is a scene in which two characters watch an episode of "I Love Lucy". Is the Plasma TV we have for the scene going to cause any flicker or other undesirable effect if I just shoot it? (i was recently told that it wouldn't)

I would appreciate any advice

Thanks ahead of time


The last time I shot a Plasma (Panasonic model) there was pulsing like with an out of sync HMI lamp. We fixed the issue by shooting with a shutter angle of 144 degrees (Varicams let one select shutters like on film cameras). In the f900 use the syncro scan to find a shutter speed that gets rid of the flicker, probably close to 1/60th second.
  • 0

#8 Christian Vandervort

Christian Vandervort
  • Basic Members
  • PipPip
  • 10 posts
  • Student
  • Los Angeles

Posted 02 August 2006 - 03:56 PM

Everything went as planned... thanks for the help guys

KV
  • 0

#9 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19769 posts
  • Cinematographer
  • Los Angeles

Posted 02 August 2006 - 08:04 PM

Everything went as planned... thanks for the help guys

KV


So what did you do? Did you have the adjust the shutter?
  • 0

#10 Christian Vandervort

Christian Vandervort
  • Basic Members
  • PipPip
  • 10 posts
  • Student
  • Los Angeles

Posted 18 August 2006 - 02:46 PM

So what did you do? Did you have the adjust the shutter?


sorry for the long delay...one student shoot after another.

No, it ended up being quite easy. I did a quick test with the shutter ON at 1/48, and upon playback on an HD monitor- everything looked flawless.

Thanks again
  • 0


The Slider

Broadcast Solutions Inc

Wooden Camera

Gamma Ray Digital Inc

Opal

Technodolly

Abel Cine

Tai Audio

Metropolis Post

FJS International, LLC

rebotnix Technologies

CineLab

Media Blackout - Custom Cables and AKS

Willys Widgets

Aerial Filmworks

CineTape

Ritter Battery

Glidecam

Rig Wheels Passport

Paralinx LLC

Visual Products

Ritter Battery

Abel Cine

Aerial Filmworks

Opal

Technodolly

FJS International, LLC

CineTape

Visual Products

Willys Widgets

Wooden Camera

Gamma Ray Digital Inc

Rig Wheels Passport

Glidecam

rebotnix Technologies

Metropolis Post

Broadcast Solutions Inc

The Slider

Paralinx LLC

Tai Audio

Media Blackout - Custom Cables and AKS

CineLab