Stop Press! ZEBRAS get Loose on PAL Colour Bars? at DVinfo.net

Graham Bernard · July 29th, 2004, 08:06 AM

Now that I've "scaled" the dizzy heights of having a 5" monitor next to my cammie, I thought it would be a really neat idea to at least calibrate it against something. Ah, he thinks, in the digital "effects" I've got PAL Colour bars .. DEAD easy! But why .. why .. does the white section of the colour bars in the V/F and the LCD show ZEBRAS? Yes, I've got Zebras selected .. and yes I can switch them off .. that's not my point . . My point is that these Bars are created internally by the camera's software - I'm not taking in any "light". . I presume. So HOW in everything that is David Lean, do I get Zebras on the Colour Bars? It just doesn't make sense! And before you ask, I get in Easy, Auto and Manual modes . .

So Gurus, what gives?

.. oh yes, the monitor is nicely calibrated now. Question still stands . ..

TIA,

Grazie

Ken Tanaka · July 29th, 2004, 10:59 AM

The zebra indicator has no relationship to anything in front of your ccd's. Zebras are produced based on the video signal behind the ccd's. That is, the camera is reading the signal's luminance, comparing that to the level of zebra display you've selected, and painting the areas that meet or exceed that level.

In the case of the white block on your SMTE bars, which is 100 IRE, zebras should be painted in that area and that area alone.

Graham Bernard · July 29th, 2004, 11:20 AM

Excellent! So Ken, if they are ONLY on my WHITE area - and they are - I'm good to go with calibrasting my 5" monitor to these - eh?

The big clue here was your, "Zebras are produced based on the video signal behind the ccd's." .. AHah!

Grazie

Ken Tanaka · July 29th, 2004, 11:42 AM

Grazie,
Zebra displays have nothing whatsoever to do with your monitor (or viewfinder or lcd panel). They are merely an indicator of video -signal- characteristics.

Calibration of a monitor is a wholly separate activity that relies upon a reference signal (ex: SMPTE bars) as input.

Not to discourage you, but you will only be able to perform a cursory calibration of that lcd monitor. A thorough calibration requires controls and characteristics that your lcd probably does not have. But do the best you can. It's still worth some effort.

Graham Bernard · July 29th, 2004, 12:16 PM

Are you serious!? "Not to discourage you, ... . " how on Earth could you do that, Ken? ;-)

. . and yes I do realise " . .. but you will only be able to perform a cursory calibration of that lcd monitor. " yes, that'll do me . . This aint no Sony or Pana Field Monitor .. I just wanted to get the Brights and colours "similar" - I'm gonna use the lcd for a more closer "look".

I understand that Zebs have nothing to do with what I'm trying, what I wanted to know was why they were appearing on the Digital siode of things - you've answered that. WHAT I really appreciate is your catring that i shouldn't hoodwiink myself or "lull" myself into to a false sense of security - no problem there Ken! I'll be using the "monitor" for framing and "focus" it's oky for this .. AND also to be able to standaway from the tripod and speak with the talent in front of me and to give the talent the option to see what is being filmed ..

.. bottom line here is that the Zebs appear on the Colour Bars . . I wont use them for calibration, however "poor" the calibration is, it is only for me to feel a bit more comfortable with the LCDs Brights, colours and contrasts .. I'm NOT taking the "word" of the monitor for what i film .. oh no!!!

Thank you again,

Grazie

July 29th, 2004, 08:06 AM
Graham Bernard Old Boot Join Date: Aug 2002 Location: London UK Posts: 3,633	Stop Press! ZEBRAS get Loose on PAL Colour Bars? Now that I've "scaled" the dizzy heights of having a 5" monitor next to my cammie, I thought it would be a really neat idea to at least calibrate it against something. Ah, he thinks, in the digital "effects" I've got PAL Colour bars .. DEAD easy! But why .. why .. does the white section of the colour bars in the V/F and the LCD show ZEBRAS? Yes, I've got Zebras selected .. and yes I can switch them off .. that's not my point . . My point is that these Bars are created internally by the camera's software - I'm not taking in any "light". . I presume. So HOW in everything that is David Lean, do I get Zebras on the Colour Bars? It just doesn't make sense! And before you ask, I get in Easy, Auto and Manual modes . . So Gurus, what gives? .. oh yes, the monitor is nicely calibrated now. Question still stands . .. TIA, Grazie

July 29th, 2004, 10:59 AM
Ken Tanaka Retired DV Info Net Almunus Join Date: Dec 2001 Location: Chicago, IL Posts: 6,943	The zebra indicator has no relationship to anything in front of your ccd's. Zebras are produced based on the video signal behind the ccd's. That is, the camera is reading the signal's luminance, comparing that to the level of zebra display you've selected, and painting the areas that meet or exceed that level. In the case of the white block on your SMTE bars, which is 100 IRE, zebras should be painted in that area and that area alone. __________________ Lady X Films: A lady with a boring wardrobe...and a global mission. Hey, you don't have enough stuff! Buy with confidence from our sponsors. Hand-picked as the best in the business...Really! See some of my work one frame at a time: www.KenTanaka.com

July 29th, 2004, 11:20 AM
Graham Bernard Old Boot Join Date: Aug 2002 Location: London UK Posts: 3,633	Excellent! So Ken, if they are ONLY on my WHITE area - and they are - I'm good to go with calibrasting my 5" monitor to these - eh? The big clue here was your, "Zebras are produced based on the video signal behind the ccd's." .. AHah! Grazie

July 29th, 2004, 11:42 AM
Ken Tanaka Retired DV Info Net Almunus Join Date: Dec 2001 Location: Chicago, IL Posts: 6,943	Grazie, Zebra displays have nothing whatsoever to do with your monitor (or viewfinder or lcd panel). They are merely an indicator of video -signal- characteristics. Calibration of a monitor is a wholly separate activity that relies upon a reference signal (ex: SMPTE bars) as input. Not to discourage you, but you will only be able to perform a cursory calibration of that lcd monitor. A thorough calibration requires controls and characteristics that your lcd probably does not have. But do the best you can. It's still worth some effort. __________________ Lady X Films: A lady with a boring wardrobe...and a global mission. Hey, you don't have enough stuff! Buy with confidence from our sponsors. Hand-picked as the best in the business...Really! See some of my work one frame at a time: www.KenTanaka.com

July 29th, 2004, 12:16 PM
Graham Bernard Old Boot Join Date: Aug 2002 Location: London UK Posts: 3,633	Are you serious!? "Not to discourage you, ... . " how on Earth could you do that, Ken? ;-) . . and yes I do realise " . .. but you will only be able to perform a cursory calibration of that lcd monitor. " yes, that'll do me . . This aint no Sony or Pana Field Monitor .. I just wanted to get the Brights and colours "similar" - I'm gonna use the lcd for a more closer "look". I understand that Zebs have nothing to do with what I'm trying, what I wanted to know was why they were appearing on the Digital siode of things - you've answered that. WHAT I really appreciate is your catring that i shouldn't hoodwiink myself or "lull" myself into to a false sense of security - no problem there Ken! I'll be using the "monitor" for framing and "focus" it's oky for this .. AND also to be able to standaway from the tripod and speak with the talent in front of me and to give the talent the option to see what is being filmed .. .. bottom line here is that the Zebs appear on the Colour Bars . . I wont use them for calibration, however "poor" the calibration is, it is only for me to feel a bit more comfortable with the LCDs Brights, colours and contrasts .. I'm NOT taking the "word" of the monitor for what i film .. oh no!!! Thank you again, Grazie

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