Ah to revive an old thread, does the heart good.
Been working with my OCD with Ray in CA about being obsessive in calibrating.
I seem to calibrate to the 9th degree and then some thinking its not good enough to be under 3 delta, but its got to be under 1.
I had a question about my RS25 and the GAMMA portion in the CMS and didn't understand why it stopped at 95%? The Video EQ goes to 100. Anyone?
Now throwing another question out about WHY if using the Video EQ instead, why do I need to use above 100 to get say BLUE saturation in line? But its causing my display to overdrive and cause some conflict. (like turn to red)
So is it possible to to overdrive using the internal RS25 CMS I wonder too?
I got the following from AVFoundry Eric L Herns who knows way to much.I'm quite sure there is nothing wrong with the VideoEq. The failures we've seen are basically all or none. If it makes a picture, then it's good. If there is a problem, then there is no picture.
There are a lot of subtleties to the way the calibration coefficients are calculated and used by the processing blocks. I highly doubt any two CMS implementations are the same, even if they have the same controls.
In general, it's a bad idea to set either the saturation or brightness above 100. You're going to drive something into over saturation or clipping at some point. If you think about it as a multiplier - sending a full white signal at 255 (8-bit level) with a multiplier of 117% would result in 298, which doesn't fit in 8-bits anymore.
One thing to be very careful of here is that you run plenty of high level content through it before you are done calibrating. I've heard (and seen) some calibrations that are really good by the numbers in CalMAN, and make a nice picture on most content. But then during something like an explosion scene, where the picture level is high, the whole thing clips and gives green/red flashes. Sometimes it's just "sparklies" around the bright edges. What happens is that these bright pixels go beyond the 8 or 10 bit limit and cause problems.
Some implementations will "clamp" the value so that anything >255 is limited to 255. Others could wrap so that 298 results in 42. The first method of clamping fails more gracefully as over-saturation just quietly turns to pure white. It's been a long time since we worked on that part of the Eq, so I can't really remember which it uses.
Also, since the CMS works as a linear function, there is some interdependence between the controls. Meaning you might be able to increase saturation to say 120 if you reduce luminance by 5 or so.