In a related post I mentioned using a spotlight with fog. I also enabled shadows in the fog setting. (fog applied to spotlight only). It looks excellent in test renders!
But I do see some odd artifacts within the visible fog even with high res render. I'm guessing there are options that would reduce fog artifacts. I began with the "Soft Shadows - Ultra" render settings, bumped detail to 16, and enabled Photons. I believe I could open the image as 16bit in PShop, but it will ultimately have to be printed at 8bit.
Any suggestions to improve the spoyptlight/fog render would be appreciated.