master black, gamma in advanced settings at DVinfo.net

Amos Kim · March 8th, 2007, 11:35 AM

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.

March 8th, 2007, 11:35 AM	#1
Amos Kim Major Player Join Date: May 2006 Location: San Francisco, CA Posts: 335	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?

March 8th, 2007, 12:07 PM	#3
Tim Dashwood Wrangler Join Date: Aug 2005 Location: Toronto, ON, Canada Posts: 3,637	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. __________________ Tim Dashwood

March 8th, 2007, 12:02 PM	#2
Stephan Ahonen Major Player Join Date: Apr 2005 Posts: 512	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.