Shooting a 25p project at 30p for low light (SHUTTER OFF) at DVinfo.net

Adam Levins · March 7th, 2009, 10:22 AM

Thx for all the help on the best profile for low light. I am shooting in Rio, Brazil 60htz for a Swiss project 50htz.

I have had my camera is set to 25p and I have been using 1/60 shutter on scenes that show flicker.

For low light shooting without shutter (shooting on streets at night with available light) is my best option to shoot 30p without shutter and in post convert the footage to 25p to match the rest of the project?

Here is a sample of light levels and flicker. I have a small battery powered tube light lighting the subject which I turn off towards the end of the clip: Favela Light Test at 50Htz EX1 NO SHUTTER on Vimeo

Thx, Ad

Serena Steuart · March 8th, 2009, 05:29 AM

If you are shooting 25P with shutter off then you have a shutter speed of 1/25, and I could see no flicker of the street lights in your sample. Considering that you must deliver 25P, I suggest you shoot at that unless tests show that you must do otherwise. 30P will give best flicker rejection in 60Hz lighting, but be guided by tests not by theory.

David C. Williams · March 8th, 2009, 05:40 AM

It might also be worth testing interlaced if your project can stand the drop in resolution. The EX does dual row summation in interlace, and your ISO rating doubles making it twice as sensitive. You lose some resolution in interlace, and you'll lose more de-interlacing, but it's worth a quick test to see if the trade off is worth the doubling of ISO.

Adam Levins · March 8th, 2009, 05:17 PM

Quote:

Originally Posted by Serena Steuart

I could see no flicker of the street lights in your sample.

It appears as wavy lines that are especially visible across the bottom half of the screen. I guess my question is has anyone had any experience cutting 30p into a 25p project?

Serena Steuart · March 8th, 2009, 06:53 PM

I see noise on your Vimeo post that is maybe flicker -- guess rather more obvious on your original. In that shot on Vimeo flicker seems a minimal problem.

Simon Denny · March 8th, 2009, 07:11 PM

Give 720/50p shutter off a go, I think you gain an extra stop I cant remmber. This is what I shoot in and when needed I go up to +6db of gain and it still holds the footage well.

March 7th, 2009, 10:22 AM	#1
Adam Levins Regular Crew Join Date: May 2008 Location: London, UK Posts: 33	Shooting a 25p project at 30p for low light (SHUTTER OFF) Thx for all the help on the best profile for low light. I am shooting in Rio, Brazil 60htz for a Swiss project 50htz. I have had my camera is set to 25p and I have been using 1/60 shutter on scenes that show flicker. For low light shooting without shutter (shooting on streets at night with available light) is my best option to shoot 30p without shutter and in post convert the footage to 25p to match the rest of the project? Here is a sample of light levels and flicker. I have a small battery powered tube light lighting the subject which I turn off towards the end of the clip: Favela Light Test at 50Htz EX1 NO SHUTTER on Vimeo Thx, Ad

March 8th, 2009, 05:40 AM	#3
David C. Williams Major Player Join Date: Jun 2008 Location: melb.vic.au Posts: 447	It might also be worth testing interlaced if your project can stand the drop in resolution. The EX does dual row summation in interlace, and your ISO rating doubles making it twice as sensitive. You lose some resolution in interlace, and you'll lose more de-interlacing, but it's worth a quick test to see if the trade off is worth the doubling of ISO. __________________ www.davidwilliams.com.au

March 8th, 2009, 05:29 AM	#2
Serena Steuart Major Player Join Date: Jun 2006 Location: Studio Alnitak, Melbourne, Victoria, Australia Posts: 640 Images: 3	If you are shooting 25P with shutter off then you have a shutter speed of 1/25, and I could see no flicker of the street lights in your sample. Considering that you must deliver 25P, I suggest you shoot at that unless tests show that you must do otherwise. 30P will give best flicker rejection in 60Hz lighting, but be guided by tests not by theory.

March 8th, 2009, 06:53 PM	#5
Serena Steuart Major Player Join Date: Jun 2006 Location: Studio Alnitak, Melbourne, Victoria, Australia Posts: 640 Images: 3	I see noise on your Vimeo post that is maybe flicker -- guess rather more obvious on your original. In that shot on Vimeo flicker seems a minimal problem.

March 8th, 2009, 07:11 PM	#6
Simon Denny Trustee Join Date: Jul 2007 Location: Australia Posts: 1,409	Give 720/50p shutter off a go, I think you gain an extra stop I cant remmber. This is what I shoot in and when needed I go up to +6db of gain and it still holds the footage well.