Tips for filming TFT's and Projectors

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Mat r
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Joined: Apr 11 2008

Hello All,

I have two scenes to shoot one involves several standard PC TFT screens and the other a projected powerpoint presentation (or something very similar).

What are the issues involved with this now that we've moved away from CRT?

Although we could replace the screens in post I would much rather keep it all 'in camera' but I can envisage issues with brightness (especialy for the projector) as well as refresh rates and the like.

We'll be shooting PAL DV.

Thnanks for any help.

Mat

Alan Roberts
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Joined: May 3 1999

Should be no problem. Just remember that they're balanced to daylight (D65 nominally) so will look very cold if your other lighting is tungsten. It's possible that a lcd panel has an odd refresh mechanism (some have scanning backlights to bump up the contrast), so you might have to adjust the camera shutter just as you would with a crt.

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
Also EBU Tech.3335 tells how to test cameras, and R.118 tells how to use the results.

Claire
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Joined: Apr 28 2001

That's for sure!

Sony's high end LCD's use frame blending and lot's of makes don't have proper 24Hz mode and use pull down and goodness knows what else.

What's likely to show up on a cam with the newest PAL Panasonic 100Hz plasmas Alan? I am told by someone in a PAL country who has just bought one it simply repeats each frame twice to claim 100Hz . Will we get half a picture if shooting at 25P?

Claire

Alan Roberts
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Joined: May 3 1999

Not sure about that. There's nothing wrong with repeating frame so long as they're progressive frames, it's when interlace gets in the way that things go wrong (i.e. most of the time). But plasmas muck up the exposure time anyway (it's how they get grey scale) so they tend to get away with it.

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
Also EBU Tech.3335 tells how to test cameras, and R.118 tells how to use the results.