have just bought a MAOZUA 5MP 20x-300x Optical Zoom USB Microscope from Amazon
A year ago I bought a Supereyes B008 1~500X 5.0MP USB. This was pure junk. twice the price of the MAOZUA. Sent it back.
First  photo from an Arduino UNO
This is the second photo I took.
Another one with greater magnification. Notice the silkscreen printing.
This is caused by the method of printing through a mesh.
This is with the light off.
M3 bolt