I'm primarily a gimp user, but I want something to blur an image similarly to the way a lens would blur an out of focus background. AFAIK this is essentially a circular blur/convolution (assuming circular aperture and ignoring diffraction).
The operation is very straight forward, but I've been searching for a while and the only thing I can come up with is ImageMagick:
convert image.png -define convolve:scale=! -morphology Convolve Disk:20 blurred-image.png
This is great for automating tasks, but is rather cumbersome with trial and error edits. I'd also like an alternative just to double check results. Does anyone know of a tool that does circular blur?
If someone with rep could add more tags, please do: convolution, depth-of-field
[EDIT] An example...
Custom convolutions give quite a small matrix (for example nothing close to 30x30) and I can't be bothered typing in weights. I'm also very much a fan of live previews with easy adjustments.