Embodiments of the present invention include an electron counter with a charge-coupled device register configured to transfer electrons to a Geiger-mode avalanche diode array operably coupled to the output of the CCD register. The frames each includes an upper leg secured to the saddle member, a lower leg secured to the seat post, and a bent portion formed between the upper leg and the lower leg. The housing has a concave portion at the edge line portion, and the state display section is provided at the concave portion. In response to a specific operation on the specific display region, the control section allows the plurality of keys to be displayed on the specific display region. The iron oxide is useful as a catalyst or catalyst ingredient in a wide variety of processes and in a preferred embodiment has an acicular shape. The invention also relates to an optical disk apparatus using the focus control apparatus.