That $40 USB “microscope” that pulls a crisp image of a 0402 resistor or the mint luster on a coin is mostly a triumph of supply-chain scavenging, not optics. Strip one down and you find three cheap parts doing the work: • A CMOS image sensor, almost always a low-end OmniVision or GalaxyCore part orphaned from the webcam and dashcam market. Millions are made monthly, so unit cost collapses to a few dollars. • A short stack of injection-molded plastic asphere lenses, the same lens-train tech as a phone camera module, giving genuine optical magnification at a tiny working distance. • A ring of white LEDs around the front element for shadowless, coaxial-ish lighting. The magic trick is the magnification number. “1000x” is not optical. It is calculated by comparing the physical pixel pitch on the sensor to the pixel size on your monitor. Blow a 2MP frame up onto a 27-inch screen and the math hands you a huge multiplier with no extra glass. True optical magnification on these is usual...