At the Nex-6 I have the rings with the standard lens, the 55-210 and the SEL SEL 50F18 tried. Best has me doing the handling like with the standard zoom SEL P1650. The 210er is a bit too bulky for the purpose and that in the fixed focal length lens irritates the quality, but the SEL1650 provides a good picture size and can be summed up with the zoom function, more comfortable in the Focus range. The distance is with all lenses very low and little varied. When 50F18 you can fix virtually only a fixed distance range and then mikometerweise tighten the focus. In the other of the zoom helps to a slightly larger variance.
The photos are, as far as I can tell so far, in order. The depth of field is minimal, even with smaller apertures, and the object must of course be well illuminated. With today's LED lamps is the brightness standard is not quite as difficult but then little tricky because of the proximity of the lens. I'm curious how this works in the summer in the great outdoors. (At present it is too dark and wintery).
Contact lens problems I could not tell.
The two intermediate rings are purely recommended technically and in terms of quality, so 5 points. On process itself, other manufacturers can not do anything else. There is only one hole at a distance. :-)
