Hi guys, thank you!
Asher, first about the "circles" aka bubbles question: the lens usually gives a ver smooth BG, except one shoots against highlights (here reflections of the rain water droplets on grass and Croci), then the bubbles appear.
I search russian sites, there I find those goodies at times. This one is really special, as it is a prototype and has an adjustment ring which allows to control the spherical abberation of that lens. Similar what the Nikon 105mm f2 + 135mm f2 DC-Nikkor allow to do.
That lens is a projection lens, hence has no iris and control is done only by adjustig the exposure time.
All fast lenses usually deliver this kind of smooth background rendering and shallow depth of field, , hence why I am so after them, especially those fast projection lenses.