[Frederik Barington]

Thanks Dan for your fast answer.
Impressing.

I really appreciate your explanation but must say i yet doesn’t have the knowledge to make said “relationship between a frame’s luminance and the correction” unfortunately.
I’m still very confused how this works.

As it looks now i made an expression on the “master” of the “exposure” effect on the layer. (Effects//Color correction//Exposure)

To get this to work I would copy/paste the expression you wrote to the master of said effect and then in the expression change the “thisComp.layer(“layer 1″” to the actual layer i want to match.

Yet I don’t know what other changes I’m supposed to make.

I’m sorry if I’m too needy.

All the best
Frederik

[Frederik Barington]

Question:

I know it’s been 6 years since you posted, and would be surprised if you would actually answer. Yet I’m still trying.

I’m not good with expressions at all. How can I use this expression to control the exposure of a shot? I have some footage with a wearying light intensity and I want to match it in with another clip, but I dont want to hand track the intensity.

Can I somehow use this expression? I’ve tried a couple of times, but have a hard time understanding what the expression literally means.

Thanks
– Frederik B

sampleSize = [10,10];
target = thisComp.layer("layer 1");
samplePos = [target.width,target.height]/2;
rgb = target.sampleImage(samplePos, sampleSize, true, time);
hsl = rgbToHsl(rgb);
hsl[2]*100