cheapLensKernel v1.1

lensKernelCheap replicates the effect of Bob Roesler's LensKernelFFT gizmo, but cheaply. The FFT version is a good way to add some realistic lens abberations, but it's pretty heavy for what is mostly just a softening filter.

This cheap version replicates that softening by mixing a bunch of blurs together with channel offsets, which were manually adjusted and balanced to match the kernels provided with the FFT version. The only time I've really noticed significant differences between them is on high values that would start to reveal glints in the HDR image kernel.

According to Nuke's performance profiling, lensKernelCheap was about 10 times faster than LensKernelFFT on a 3840x2400 test image, far faster to work with. It has the option to switch to the FFT version, and also to force the FFT version when rendering from a non-GUI Nuke.

You'll need to add the filepaths to the .EXR kernel files onto the read nodes inside the internal FFT node. The files are accessible through google in several places, such as this github folder.

Sample images:

Version history:

1.1 - better wrapper controls for internal FFT version
1.0 - initial upload