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Setting Zebras


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#1 John Dorfax

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Posted 23 April 2009 - 08:17 AM

OK, I need to end this once and for all. I've searched the forum high and low and can't seem to find a straightforward answer to this:

Many times people talk about setting their Zebras to 100 or setting their Zebras to 70 but
people rarely mention that those numbers are not always the actual IRE they allegedly should represent, right?

For example, in just about every video camera I shoot on, I like to have my Zebra 1 set to 80 IRE and my Zebra 2 set to 100 1RE. I would be wrong to just go into the menu settings for Zebras and set them to the numbers 80 and 100 because not all cameras would be calibrated perfectly right?

Hence, and now here is the main question: to set my zebras to represent true 80 and 100 IRE, I should flip up color bars and do the following, right?

With bars up, to set my Zebra 1 to true 80 IRE, I should toggle the numbers starting in the 60s upwards...upwards...till...wait...BAM the gray bar on the left (which I have been told is a true 80 IRE bar), lights up with zebras. Now I know this number weather it be 74 or 86 is actually representing true 80 IRE. I then do the same for the 100 IRE zebra, only I correspond it to the white box at the bottom (which is indeed, true 100 IRE)

Please assume this is a checkout without being able to use a waveform monitor or even a color field monitor. Imagine this: show up to a production company office, they hand me a broadcast camera with no monitor and say "make some television with this."

Thank you all in advance for settling this seemingly simple yet unsolved issue in my DP existence.
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#2 Chris Keth

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Posted 23 April 2009 - 09:49 AM

I've never heard of setting your zebras by color bars. That's basically checking the ruler you will use to build a table against your other ruler.

To my understanding, the zebras just highlight what parts of the image will be recorded at the set IRE level. It's a hard programmed fact that can not change like monitor calibration or white balance can. Likewise, the color bars are a standard signal that will never be different from camera to camera, provided it is generated properly and not photographed off of a monitor or something silly like that.

If you set 80 IRE zebras, you always get 80 IRE zebras. Not 75, not 85.

If anyone else knows different, they will surely correct me, but I have never heard of what you're talking about and every DP I've ever worked with has just told me a number they want the zebras set at.
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#3 Etienne van Leeuwen

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Posted 09 May 2010 - 01:03 PM

Hi all,

I'm sorry I'm so late with my reply on this one....

Actualy, it depends on the zebra apt level. Bring this down to 1% and then scroll the zebra det level down. I think it's not popping in on 80% but at 75%. Scroll up one number (75-76%) and the zebra is gone. BUT.... Set the apt level on 2% and zebra one is there again. So it's a combination of apt level and det level. Th apt level is telling WHEN zebra is coming in (like a warning).
I really don't know the true answer on this.

this is indeed a very "old" discussion....

Regards,
Etienne
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