Anyone else driving or having to drive their Video EQ saturation and or brightness or both in the CMS beyond 100 to get a calibrated picture?
Eric at AV Foundry doesn't recommend it,
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.
But why then do we have the option to go beyond 100 and stretch it out from 0-200 then?
Seems in low lamp I don't have enough brightness?