I am curious what other folks are using for a correction factor for Nikon's 105mm macro lens. I did some testing with this lens on my D810. I determined that I could use CF 1.8 without seeing any out of focus banding. I did try CF 2.1 but saw some very faint banding. In a real world this would probably work, but wanting to be safe I will be using 1.8. This has significantly reduced the number of images in a stack.
If anyone is interested in the details of my testing, I will be glad to send you a copy. Contact me at : alankiecker@charter.net