7.5 Ire at DVinfo.net

Arturo Glass · November 16th, 2007, 06:59 AM

When making sure that I am within "legal" limits of blacks, is this something I can do in post or should i be concerned with it during the shoot itself? If I shoot with the zebra pattern, being sure there is a good amount of contrast in the image, am I ok then to make necessary adjustments in post, or do I need to set a 7.5 IRE during the shoot?

Ron Evans · November 16th, 2007, 08:10 AM

Do it in post if you have to. All digital is equivalent to 0 IRE. DVD's are equivalent to 0 IRE the player applies the required setup for NTSC TV's. The only time you may have a problem is going from the computer directly to tape ( like VHS)

Ron Evans

Glenn Chan · November 16th, 2007, 03:37 PM

In most cases, the (misleading-named) "7.5 setup" setting on your camera should NOT be used. It will create non-standard digital levels.

2- There is no IRE in digital formats. Digital formats record in bits. The 7.5 IRE setup issue arises when you convert from those digital bits to analog... does digital black level (code 16 Y' for 8-bit Y'CbCr formats) get converted to 0 IRE, or does it get converted to 7.5 IRE?

3- See the article:

http://glennchan.info/articles/techn...5IREsetup.html

November 16th, 2007, 06:59 AM	#1
Arturo Glass Regular Crew Join Date: Oct 2007 Location: Los Angeles, CA Posts: 29	7.5 Ire When making sure that I am within "legal" limits of blacks, is this something I can do in post or should i be concerned with it during the shoot itself? If I shoot with the zebra pattern, being sure there is a good amount of contrast in the image, am I ok then to make necessary adjustments in post, or do I need to set a 7.5 IRE during the shoot?

November 16th, 2007, 08:10 AM	#2
Ron Evans Inner Circle Join Date: Mar 2003 Location: Ottawa, Ontario, Canada Posts: 4,220	Do it in post if you have to. All digital is equivalent to 0 IRE. DVD's are equivalent to 0 IRE the player applies the required setup for NTSC TV's. The only time you may have a problem is going from the computer directly to tape ( like VHS) Ron Evans

November 16th, 2007, 03:37 PM	#3
Glenn Chan Inner Circle Join Date: Jun 2003 Location: Toronto, Canada Posts: 4,750	In most cases, the (misleading-named) "7.5 setup" setting on your camera should NOT be used. It will create non-standard digital levels. 2- There is no IRE in digital formats. Digital formats record in bits. The 7.5 IRE setup issue arises when you convert from those digital bits to analog... does digital black level (code 16 Y' for 8-bit Y'CbCr formats) get converted to 0 IRE, or does it get converted to 7.5 IRE? 3- See the article: http://glennchan.info/articles/techn...5IREsetup.html