A lens is typically made from glass (Silicon or Quartz) or plastic; both are electrical insulators. So, in general, electrons are inhibited or blocked from passing thru this material. Light is reflected off the environment being sourced from the sun in daylight, naturally. A camera lens brings these waves of photons to a focus with various wavelengths converging together on a plane. When enough of these waves arrive on the focal plane, the imaging detector (CMOS or CCD) can convert this photon pool to electron information which is moved along to a display.
Photons behave similarly to electrons, sharing both wave and particle characteristics. As electromagnetic wavelength decreases, energy content and smaller size resolution increases. Photons are considered without mass according to the study of Physics.
Fundamentally, time and (light) energy form the core of this process. Light waves can be somewhat random or orientated - meaning polarized; traveling along a helix; traveling up and down or left-right. This polarization can be changed with a mirror or prizm.