Hi @sankos and @heckflosse !
I have tested your hack on the sharpening module, with the Lab blending, but I still find it too harsh for my taste on the D810 pictures. Maybe just a matter of taste, but anyway, the unsharp mask remains a quick and dirty way to make the local contrast pop up.
I have never used the RT deconvolution, but if the deconvolution is performed as @heckflosse suggests, only on the L channel, well you have one third of the computations I do. The benefit of performing the deconvolution on RGB channels is you often have a spatial phase change in the 3 channels since the light transmission and deviation inside a lens is wavelength-dependent. Especially, over F/11, you get more diffraction in the red (800 nm) than in the blue (400 nm). So, dealing with the color signals helps correcting that, but doing it on the L channel is definetely possible as an approximation.
Also, what I do is a blind deconvolution with regularization, and I believe RT performs a regular Richardson-Lucy. The regularization performs 8 gradients evaluations per iteration (on the 8 neighbouring pixels) and damp the pixels having an abnormal gradient, which helps avoiding noise amplification and ringing. The blind aspect means you don’t need to pass a blur profile to the algorithm (and possibly give a wrong one, which could only diverge after a certain number of iterations), the algorithm estimates the blur itself and refines it at every iterations. But that’s 2 additional heavy operations to perform. So that’s the cost of the accuracy.
And finally, my programm is not fully optimized, written in an interpreted language for prototyping purposes, and the RT version should be compiled, so much more efficient.