Aliasing issue with "Don't affact colors" and "intensity exponential"

[Yannick]

Hi,
I had this problem for quite some time where I get some aliasing problem and I finally narrow it down to this.
If I use the color mapping type to be "intensity exponential" and use a linear workflow with "Don't affect colors" I get some grain around where my light light my objects.
I have attached an image and the file.

Changing the color mapping type fix this issue. is this a bug? or normal? why is it doing this?

Thanks,

Yannick

[Yannick]

Bump Anyone?

[ricoholmes]

Not sure it's related, but have you tried "clamp output" ? I find that helps a lot with aliasing problems if you're not outputting 32bit.
(also Lanczos filtering is best reccomended "off" - it's a sharpening filter and better left to post work unless absolutely nescessary).