Now after several years of looking for an everyday microscope suitable for a busy family I found one: The Brock Magiscope #70 is exactly what I had wanted. It has a single-moving part that my 5-year-old son could handle. He could put a leaf in and focus it right. Rubber bands hold the slide. For light the scope uses a fat fiber optic bent pipe which channels ambient room light to the underside of the objective lens (no electricity). There is no fussing, no adjustments. The viewing field is amazingly bright and clear, good enough for high school work.
or smart phone to its eyepiece, and get pretty good microphotography shots. And best of all it is practically indestructible. The thing is simple and rugged as a hammer. In fact, it was built for the abuse of K-12 classrooms, which is probably as grating as a war. I know one educational sailing company that keeps several on its boat – probably the most challenging environment anywhere for optics. Brock offers a “lifetime replacement warranty, including accidents.” If it breaks, ever, they replace it. And they do. (Some visiting kids managed to break the light optic – I have no idea how – but Brock replaced it with no questions asked. This tool is always on, always out (it sits next to the fruit bowl); we use it.