Videoscopes: What to look for?

kentwolf wrote on 8/21/2004, 8:23 AM
I currently have a need to color correct a substantial quantity of poor video footage. Usually, my footage has been good, so I have not had a need for this. This is new ground for me.

I think I have a pretty good feel for using the color corrector, secondary color corrector, color curves, and the HSL adjust.

My root question: What constitutes a good distribution on the Vegas videoscope?

I haven’t really found this information in this forum nor in the Help file.

1.) I have seen footage look good with an almost (imperfect) near-circular distribution, kept just within the bounds of the second circle from the center.

2.) I have also seen footage look good with almost left-leaning (fat) slash pattern, again, kept just within the bounds of the second circle from the center.

3.) I have also seen footage look good with a tight distribution near the center, first circle as well as a wide distribution, first circle.

I would think that there would be a utopian goal as far as what the videoscope should look like.

Is there a web reference as to what I should be looking for?

I know I can also make it look good on my external monitor, but the videoscope seems nice as far as more precisely (and faster) quantifying my output.

I really think I can pick up on this pretty fast and am pretty excited about it. I just need a frame of reference as to what should I be seeing on the videoscope.

Can you help?

Any other input or opinions would be very welcome.

Secondary question, if you can: With respect to the color corrector (primary), I see that you can adjust the highs, mids, and lows. When using the dropper tool and sampling a video frame, would it be accurate to say that, say, if using the high dropper tool, you have now just redefined your highs? If not, what sort of frame of reference denotes the highs by default? In general, what colors constitute highs, mids, and lows?

Thank you very much for your help!

Comments

riredale wrote on 8/21/2004, 1:47 PM
I am by no means an expert with the scope, but can offer a couple of thoughts:

(1) I am not sure you can or should look to an overall circular pattern as an example of a well-balanced scene. Frankly, the only real use I've had for the vectorscope is to ensure that the colorbar colors were located where they should be.

(2) To colorbalance an image, I've heard it said that you look for items that should be white, grey, and black, and just use the inverse color eyedroppers to make them so.

(3) For me the most useful tool is the histogram. You look at the distribution pattern of a gorgeous video clip, and then try to get the same approximate distribution with your own video.
kentwolf wrote on 8/21/2004, 5:49 PM
Thanks for the input!
FuTz wrote on 8/21/2004, 5:49 PM

Maybe there's info at www.wideopenwest.com (hopefully!)
kentwolf wrote on 8/21/2004, 5:52 PM
>>www.wideopenwest.com

Looks like it's dead...
beerandchips wrote on 8/21/2004, 5:58 PM
Want to learn about Video Scopes and how to PROPERLY use them. Find a book on them and read it.
jetdv wrote on 8/21/2004, 6:20 PM
How about this url:

http://www.wideopenwest.com/%7ewvg/tutorial-menu.htm
smhontz wrote on 8/21/2004, 6:49 PM
Go get the book "Color Correction for Digital Video" by Steve Hullfish & Jaime Fowler. It'll tell you how to use the scopes.
kentwolf wrote on 8/21/2004, 7:58 PM
>>...Go get the book ...

I actually called Barnes & Noble and Borders and no one has it. It will take them a week to get it.

I will pursue this though.

Wow! I didn't know this was such a big seller! :)

Thanks all!
rs170a wrote on 8/21/2004, 8:15 PM
There's an excellent series of video test & measurement application notes (look at #12, 13 & 14) from Videotek .
Tektronix also has articles on , and .

Mike
Spot|DSE wrote on 8/21/2004, 8:41 PM
If you can find a copy, Tektronics did an EXCELLENT video a few years back. I've copied the VHS and put it to DVD as a storage. Also, Steve Hullfish's book, entirely in color, is a must-have, IMO. He goes through scopes in a very simple, straightforward manner before he starts into more difficult discussions, offering you the opportunity to learn small, or learn big, depending on how deep you want to go.
kentwolf wrote on 8/21/2004, 9:32 PM
>>...Steve Hullfish's book, entirely in color...

Ahhh! That explains to $40-$50 price.

I will get it.

Thanks!
farss wrote on 8/21/2004, 11:11 PM
To me histograms seem more useful than the vectorscopes. Vectorscopes and waveform monitors traditionaly relate more to working in analogue land where you may need to adjust for phase and gain errors. Histograms to my eye at any rate give you a better picture of the distribution of color within a frame. Steve's book gives excellent examples of how to use scopes to see errors in adjustments and equipment calibration.
But once it's 'in the can' so to speak and in the digital domain a lot of this isn't so relevant. But getting back to the original question, there's no such thing as a 'right' set of vectors or parades or whatever, just as there's no correct level for dialogue or sonogram for music.
All these are tools that will show you the limits but within those limits anything could well be correct, if it was all that simple we could build cameras that took a perfect picture everytime or recorded perfect audio.
Record someone whistling 30 from the camera wearing a red clowns suit that fills the frame. What should that look like on a vectorscope? What level should the audio be at? What should the sonogram look like?
By far the best tools are your eyes and ears and good monitors to feed the information to them so your brain can make informed decisions. If you've got two shots of the clown and you want the red suit to look the same then scopes are useful for making a comparative evaluation, but as to what absolute color it should be is another matter entirely. Same goes for the sound, meters will let you make certain the levels are the same, they'll let you see you're not clipping or buried in the noise floor but between those limits there is only one way to evaluate the right level, it's one that matches the subjects distance form the camera and no metering system can evaluate that.
You also need to factor in where the material will be viewed, for TV I wouldn't loose much sleep over it being 'right' so long as there's good matching between shots. Cinema requires tighter matching because the audience is totaly focussed on the screen but have less color reference than a TV viewer so you can be further off 'correct' and so long as it's consistent the eye will adjust.

In short read the book SPOT recommended!
PS, bought mine through Amazon.

Bob.
smhontz wrote on 8/22/2004, 8:50 AM
I always start my book searches by going to www.addall.com. It searches many bookstores for you. Lately it's been finding the best price for books at Overstock.com. And there you will find "Color Correction for Digital Video" for 28.99 + 1.40 shipping.

I use Overstock.com a lot - excellent service and good prices.
kentwolf wrote on 8/22/2004, 10:56 AM
>>...Overstock.com. And there you will find...

Thanks for the info!

I just ordered it. That is a very substantial savings.

Thanks again all!