I picked up a used copy of the Canon EF-M 28mm f/3.5 Macro IS STM lens in 2019. I didn't pay much for it. I never really used it very often. It was a unique lens. It had built in LED lights at the end of the lens. These could be turned on or off as needed. Pretty novel. This was a built in ring light for macro photography. I had fun with this lens. For such a light and small lens, it was surprisingly sharp. It was quick to focus and snappy.  It was a really fun lens to use. If you are going to use any of the EF-M series bodies, be sure to pick up a copy of this lens. Well worth it. I eventually sold it when I moved away from the EF-M system in 2021.