The tube can be dimmed, which I have so far, however, always on full blast, as 75 watts are not necessarily a lot and one should get used to the thought of having to sensitivity (ISO) screw up his camera. In modern SLRs my opinion, but not really a problem.
Whoever comes up with the idea to look for something more powerful, should note that the photo right model centered purely looks into the light, which is very troublesome for the eyes at 75 watts.
Overall I am very satisfied with the offered here Walimex Ring Light. The price performance ratio is correct, therefore I also 5 star.
PS: Buyers should read once about burning of fluorescent tubes in the Internet. Had to tip read in a blog, there was also me all previously unknown.