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-   -   master black, gamma in advanced settings (https://www.dvinfo.net/forum/jvc-gy-hd-series-camera-systems/88484-master-black-gamma-advanced-settings.html)

Amos Kim March 8th, 2007 11:35 AM

master black, gamma in advanced settings
 
This may be a basic question but does anybody know what the master black does? And I read in the manual, that adjusting the gamma level up or down increases or decreases the "tonality" in the blacks or whites. What do they mean by "tonality"? Does it mean more detail in the blacks or whites?

Stephan Ahonen March 8th, 2007 12:02 PM

Gamma basically affects the mapping of brightness values between black and white. If you're familiar with the Photoshop Curves tool, gamma would be like grabbing the middle of the curve and moving it up or down. Doesn't really affect blacks and whites, mostly operates on midtones.

Master black is like grabbing the far left handle in the Curves tool and moving it up or along the bottom of the graph toward the right. It basically lets you crush your blacks or turn them into greys, but in a different way than black stretch. Black stretch is like a gamma that only operates in the bottom couple of percent of the brightness scale.

The best way to figure out what any video adjustment does on a camera is to plug it into a monitor and fiddle with it to see what happens. Just remember to write down what it was beforehand.

Tim Dashwood March 8th, 2007 12:07 PM

I'll direct you to this quicktime file of waveform grabs from the HD100 shooting a linear chart while I changed every setting in Advanced.

http://homepage.mac.com/timdashwood/...X-Sorenson.mov

Step through one frame at a time.


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