Previously I had posted on the Pixco Nikon G to Micro 4/3rds focusing helicoid, which filled a need in my UV-imaging setup. However, it does have significant play in the adapter which can affect the accuracy of fine focusing. Hence I decided to take the plunge and get the one from Fotodiox, which is said to be in their Pro adapter line.
This adapter arrived on Tuesday and does look identical to the Pixco helicoid. But the focus mechanism feels firmer and there is definitely much less play now with my UV-imaging setup. Definitely the best Nikon to Micro 4/3rds focusing helicoid available.
As I am using this helicoid focuser with my Coastal Optics 60mm F4 APO and the D-Focus v4 follow focus system, I have had to set the focuser to be slightly forward of the gear ring on the lens. That way it can continue to serve as focuser even with the helicoid focuser extended to maximum. And it does work, see below.
The very minimal play in the adapter is largely due to the fact that the Coastal Optics 60mm APO has a fairly stiff focusing ring which requires significant force to adjust focus (much much more than any other lens I own); I do not think this will be an issue with other lenses, unless they have tight focusing mechanisms like this lens.
Verdict: Costs more (US$69.95) than other such adapters on eBay. But is well constructed (as with Fotodiox Pro adapters), works well with very minimal play. Highly recommended.