The Bouncing and Bending of Light
Reflection, refraction, absorption. This is a large microscope slide made into a lens by a dimple cut into it, on top of a shiny optical table. At optical wavelengths, the glass or plastic of the microscope slide is minimally absorptive.
Beamline 12.0.2, Advanced Light Source, Lawrence Berkeley National Lab.
Sigma 30mm f/1.4 @ f/2.8.