I don’t know where I first saw the instructions, but it mentioned using any CD drive/player lense. I used an old 40x CD computer drive (which in itself was fun and enlightening to take apart). When it finally came down to separating the tiny lense from the part holding it, I used wire cutters to cut away most of the plastic, but it turned out that the “glue” holding the lense came off the lense very easily like it was just silly putty.
I recommend this great instructable that uses a
cat toy laser pen lense. If you feel the need to go overboard, your not alone.
You’ll need a flashlight because you block most of the light when you are 2mm away from what you are photographing. This is my finger print without a flashlight but I had good lighting above and skin is semi-translucent.
Holding the camera steady at just the right distance is not easy. The CD drive’s laser’s lense that I used yields such a small depth of field that I taped a column of 0.5cm square pieces of paper to either side of the lense so that I can easily get (and hold) the camera parallel to the surface of flat surfaces I want to photograph. In the pencil on paper photo I simply lifted the end of the camera nearest the lense, but even with such a slight angle to the surface only the middle portion was in focus. Only the top surface of a surface mount resistor is in focus and they are only 0.25mm high!
The last photo below shows millimeter marks on a ruler, so you can compare the objects in the other photos to see how big they are.