Would this work with a far away light source indoors, like a bright lamp across the room? There's a liquid component to my lens and I don't want it to freeze outside.
I have fabricated a few biconvex lens (12mm diameter) for an experiment and am trying to find their focal lengths. My though is to set up three parallel lasers and find where the beams converge. However, even with the smallest laser diodes I could find, three beams surpass the diameter of the...