A self educated farmer, Bentley attracted world attention with his pioneering work in the area of photomicrography, most notably his extensive work with snow crystals (commonly known as snowflakes). By adapting a microscope to a bellows camera, and years of trial and error, he became the first person to photograph a single snow crystal in 1885.
He would go on to capture more than 5000 snowflakes during his lifetime, not finding any two alike. His snow crystal photomicrographs were acquired by colleges and universities throughout the world and he published many articles for magazines and journals including, Scientific American and National Geographic.