Einstein didn't directly *study* photons in the way we might think of it today, with lab experiments and advanced equipment. His work on photons was primarily theoretical, building upon the work of other scientists and using thought experiments to develop his ideas. Here are some key scientists and their work that Einstein drew upon:

* James Clerk Maxwell: Maxwell's equations unified electricity and magnetism, predicting the existence of electromagnetic waves that travel at the speed of light. This laid the groundwork for understanding light as an electromagnetic wave.

* Heinrich Hertz: Hertz experimentally confirmed Maxwell's predictions, generating and detecting radio waves, further solidifying the wave nature of light.

* Max Planck: Planck introduced the idea of quantized energy, suggesting that energy could only be emitted or absorbed in discrete packets called quanta. This concept, applied to light, led to the idea of the photon.

* Albert Michelson and Edward Morley: Their famous experiment demonstrated that the speed of light is constant, regardless of the observer's motion. This finding contradicted classical physics and paved the way for Einstein's special relativity.

Einstein took these ideas and used them to explain the photoelectric effect, a phenomenon where electrons are emitted from a metal when light shines on it. He proposed that light energy is quantized into packets (photons), and the energy of a photon is directly proportional to its frequency. This explanation, which contradicted the wave theory of light, won him the Nobel Prize in 1921.

So, while Einstein didn't directly conduct experiments with photons, his work built upon the groundbreaking research of others and revolutionized our understanding of light.