View Full Version : Manual Knee Function


Jack Foster
April 3rd, 2007, 01:37 PM
Hi
My understanding of the knee functions is that it extends the latitude of the highlites. So if your subject is standing in front a bright window the knee will bring the bright window closer to the exposure of your subject.
The JVC HD cameras have manual knee control. How does changing the percentage level of the knee effect the image. The manual has no explaination. Thanks for your help
Jack

Joachim Claus
April 6th, 2007, 03:27 AM
Hallo Jack,
Tim Dashwood published a Quicktime movie which shows all effects of changing menue settings of the HD100. If you go through it frame by frame you can check the various effects of menue settings. You can find it here:

http://www.dvinfo.net/conf/showthread.php?t=88724

Regards,
Joachim

Jack Foster
April 6th, 2007, 11:09 AM
Hi Jaochim;
Thanks for the link. Tim's QT movie is a good visual demo of what's happening with the manual knee setting.
thanks
Jack

Greg Boston
April 6th, 2007, 11:24 AM
Hi
My understanding of the knee functions is that it extends the latitude of the highlites. So if your subject is standing in front a bright window the knee will bring the bright window closer to the exposure of your subject.
The JVC HD cameras have manual knee control. How does changing the percentage level of the knee effect the image. The manual has no explaination. Thanks for your help
Jack

The knee refers to that portion of the gamma curve towards the top as it curves to the right from more or less vertical. The horizontal axis of the graph represents black to white while the vertical axis represents the signal level. Adjusting the knee is adjusting the sharpness of the curve so that highlights gently taper off, or go to maximum rather quickly as you approach the right side of the graph(maximum white).

-gb-