Scene File screen items: Chroma Level, Chroma Phase, Detial Level, Detail Coring.....

[c3kings]

Dear All,
I am playing around Scene File function. I am wondering the differences between chroma level and chroma phase. I mean in a technical terms. Visually, when I turn chorma level to negative, the color looks less saturated. But for chroma phase, I don't see much difference.
Another pair that confuses me are Detail Level and Detail Coring. Is Detail Corning just for noise reduction and nothing to do with enhancing the detail?
Lastly, about A. Iris Level, does A. Iris Level mean to automatically choose the best exposure already? Why we still can choose different levels?
Someone told me that there is a web page explaining all the options. Does anyone know about it?
Thanks in advance for any inputs and inspiration!
King

[Jim Carswell]

You might want to pick up Barry's book. it will answer all of the questions you asked.
Jim

[ullanta]

Yes, Barry's book, and many (old) posts will answer a lot of this in detail. But briefly:

chroma level is as you said, reduces the overall amount of color, while chroma phase shifts color towards one end of the spectrum or t'other.

Detail level is basically "sharpening", while detail coring tries to smooth out noise in more-or-less uniform areas of the image.

Auto-iris is indeed when the camera chooses the Iris setting; however, whether it chooses the "best" setting is questionable - this is usually an artistic decision, and the camera doesn't even have quite enough intelligence to make even a good technical decision all the time. "Auto Iris Level" lets you bias the auto-iris towards a larger or smaller aperture - so, for example, if you have a spotlight or backlight situation, you can give the auto-iris function a bit of a hint so it can handle it a little better.

[c3kings]

Thanks, Jim and Ullanta,

Yes, Barry's book looks very attractive. I will save up to buy it.

By the way, Ullanta, are you saying that detail corning is for smoothening the noise, but nothing to do with sharpening? It follows that to my understanding, generally, it will be a good application when I push the gain to, say, 12db. Am I correct?

Thanks a lot.

King

[ullanta]

Sharpening and coring do interact (as discussed to be repetitive in Barry's book!) - sharpening (detail level) tries to find edges in the image, and emphasize them. Coring tries to find areas without edges, and smooth them. Gain increases noise, which means higher levels of sharpening will turn some of the noise into "false edges". I'm not 100% sure of the order in which these processes take place (that is, coring before sharpening, or vice-versa - though from my days in vision processing I'd guess (hope?) that coring would come first. In any case, it seems that coring and detail have the best effect when used together; with a high level of detail, coring will have a stronger effect, while at low levels of detail, coring doesn't do much...