The battery for the lighting is in the delivery. The white LED illuminates the field of view enormously bright, but is in delivery condition but also completely useless. It projects namely as laterally into the beam path, that they also unshielded lights directly into the eye upward. It is therefore only blinded and recognize them as good as nothing. Fortunately, the problem is easily resolved: I just stuck a scrap of black electrical tape with tweezers on top of the LED. The samples illumination worked fine.
Since, however, a not inconsiderable design flaws, there's two star deduction. Otherwise highly recommended.