What are the differences between the Canon EF 50mm 1.8 II and STM lenses?

The main differences between the Canon EF 50mm 1.8 II and STM lenses are in their autofocus systems. The EF 50mm 1.8 II has a traditional motor-driven autofocus, while the STM lens has a quieter and smoother autofocus system that is better suited for video recording. Additionally, the STM lens may offer slightly improved image quality and overall performance compared to the EF 50mm 1.8 II.