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Sony VX2100 / PD170 / PDX10 Companion
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Old May 21st, 2005, 07:47 PM   #1
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zebra lines

On my vx2100 its possible to switch zebra between 70 and 100. But what that exactly means? I know that zebra shows illegal colors for broadcast, am i right? And whats the difference between 70 and 100 then? And if you see these lines, that means that settings are wrong and i should change them?

thanks!

(tried to search, could'nt find answer)
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Old May 21st, 2005, 09:15 PM   #2
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The zebra stripes don't show illegal colors, they indicate areas which may be overexposed in your video.

Generally speaking, if you set the zebra level to 70 IRE when stripes appear on caucasian skin, it's on the verge of being overexposed. If you set the level to 100 IRE, then stripes indicate areas of the image which will be completely white without any detail.

A search turns up some helpful stuff, especially if you limit it to this forum:

http://www.dvinfo.net/conf/showthrea...ighlight=zebra
http://www.dvinfo.net/conf/showthrea...ighlight=zebra
http://www.dvinfo.net/conf/showthrea...ighlight=zebra
http://www.dvinfo.net/conf/showthrea...ighlight=zebra
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Old May 23rd, 2005, 12:11 PM   #3
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thanks a lot
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Old May 24th, 2005, 12:06 PM   #4
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one more question:

is zebra only indicator which shows what is wrong and not, or it actually adds something to your final recorded footage?
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Old May 24th, 2005, 01:03 PM   #5
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Zebra stripes are only shown in the viewfinder & LCD, they do not appear in the recorded video.

As an aside, generally the 100% IRE zebras allow for a little bit of safety before you get to full white. Not much but a little.

However, you should always test the tools before you need them for money shots.
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Old May 28th, 2005, 09:01 AM   #6
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Important Note Andzei: You can stop up or down past your zebras and under or overexpose in 70 IRE if you don't pay attention. In other words the zebras show their respective IRE level. not more, not less. Do this: In a well lit room set up a shot with some skin tone objects. Then with your zebra set at 70 IRE set your exposure to your liking and roll tape. Now stop up and call out your iris settings as you go untill all the zebras are gone then start stopping down. You will see the zebras reappear as the exposure becomes correct then disappear again as you overexpose the shot. You can then watch the tape and learn how your camera works.

I use 100 IRE zebras. White is white is white, skin tones vary greatly. Additionally, 100 IRE is maxed out white. When zebras appear at the 100 IRE setting they won't disappear as you stop down because you can't expose more than 100 IRE. I like knowing that I'll have a viewfinder full of stripes I can't miss if I'm overexposed.
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Old May 28th, 2005, 11:01 AM   #7
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Using the 100 IRE Zebra setting is OK for some work but when the face is the most important object to correctly expose in the scene, then that setting isn't much help. You have to rely on the 70 IRE unit Zebra patterns.

You do need some experience to shoot different skin tones correctly. But that's just an issue of practice. Regardless of skin tone, the 70 IRE zebras will help.

BTW, you should look for the zebra patterns from the underexposure direction. That is, start with the lens closed down and open up until you start to see the pattern in the oject of interest.
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Old July 1st, 2005, 02:31 AM   #8
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Quote:
Originally Posted by Mike Rehmus
BTW, you should look for the zebra patterns from the underexposure direction. That is, start with the lens closed down and open up until you start to see the pattern in the oject of interest.
Mike,

I am curious as to why it would make a difference in the exposure based on which direction from which you approach setting the aperture. If I set my aperture so that zebras only appear on the hot spots (nose, cheeks), why would I not arrive at the same f-stop regardless of whether I approach from higher f-stops or from lower f-stops?
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Old July 1st, 2005, 11:32 AM   #9
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When you actually try the zebra patterns in your camera, you will see that they eventually disappear with overexposure (above the 70%). So coming down from too much light, there is very little of the zebra shown in the viewfinder. . .picture looks normal)

Coming from too little light (relative to the zebra setting) is much easier because the zebra pattern first appears in the brightest areas and 'moves' to the areas of interest in a very noticable manner.

Not so when you come from the other direction.
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