I was asked for details about my hand held microscope so decided to post about it here for others who may be interested.
The eyepiece is a small Ramsden type. I don't know the focal length but it is short, only about 1/8" in front of the field lens. The distance between the end of the eyepiece and objective lens mounting shoulder is 1.5".
As you know, magnification is determined by the respective focal lengths of the objective and eyepiece and the distance between them. The greater the separation the higher the magnification. However, the down side with higher magnification is a reduced depth of field at the object plane.
After experimenting with different separations I arrived at what I considered an acceptable separation for sufficiently high magnification and chose a transparent plastic 35mm film can to mount the optics in. The inside was darkened with a dull finish black paper and the outside covered with adhesive aluminum duct tape. In other words, I used materials I had on hand.
I've posted two pictures in my photo album. https://www.cloudyni...400-microscope/
If you like experimenting and have the optics, give it a try.
Edited by Richard O'Neill, 18 January 2019 - 11:25 AM.