Originally Posted by mark haflich
So your test showing the same lumens out does not mean that the results were the same regarding crushing or not crushing the blacks.
The process I outlined allows you to precisely dial in your BLACK/BRIGHTNESS settings. However, it won't stop you crushing your blacks, should you be determined to do so, by further decreasing the BLACK/BRIGHTNESS control below the correct setting.
The only way to ensure not crushing is to somehowmake the black bars visible (by using the Lumagen with the Sony at deefault 50 brightness and then adjusting the brightnesss on the Sony to make the bats just disappear.
It's not the only way, but it's a simple way that is available to most using widely available test patterns. But that type of pattern has it's own issues, eg if the BTB bar is -2 IRE or -4 IRE because if you adjust to the point that it's *just* not visible you may still have left the points above it visible, when they shouldn't be and your black floor will be elevated slightly.
Another way is a test pattern with the discrete digital 17,18,19,20 etc steps in it and lower the BLACK level until only those steps are visible, but that's sometimes tricky as the lowest steps can be very difficult to see whether any change has occurred.
The more objective way is to put up a 0 IRE field pattern and use a light meter - raise the BLACK/BRIGHTNESS until you see the light output rise, and then lower it again to the point that lowering it one more step makes no difference - at that point adjust it back up one step and you have the correct setting. That of course requires a light meter than can read black accurately, but it also removes any doubt from the setting...
With a YCbCr feed, and the Lumagen at default and the Sony at default the BLACK level is correct - no need to change it. There is no crushing and BTB is clipped correctly.Edited by Mark_H - 11/24/13 at 3:31am