I have been doing tests with a newly acquired JJC ES-2 clone of the Nikon ES-2 film digitiser.
. Click above image for Amazon link.
It works very well and comes with a LED light attachment which the Nikon version does not have.
The setup I used was:
Nikon D800, PK11(a), PK13, Nikkor 55mm F2.8 AIs micro and the slide/film copier.
It is a lot cheaper than the Nikon equivalent (seems made of engineering plastic like the Nikon one) and includes the LED light attachment along with 5 lens adapters.