What are the key differences between the Canon 50mm STM and II lenses, and which one would be the better choice for my photography needs?

The key differences between the Canon 50mm STM and II lenses are in their autofocus systems and build quality. The STM lens has a smoother and quieter autofocus motor, making it better for video recording. The II lens has a more traditional autofocus system but is known for its sharp image quality.

If you prioritize video recording and need a quiet autofocus, the STM lens would be the better choice. If you prioritize image sharpness and don't mind a slightly noisier autofocus, the II lens would be a good option for your Photography needs.