The Canon EF 40mm f/2.8 STM is one of Canon's hidden gems. A very inexpensive prime lens, this low-profile pancake lens turns out suprisingly sharp photos with pleasing color. Sharp corner to corner, this lens punches way out of its weight class. I bought my copy on ebay in early February 2017. These are easy to find in the used market (I have no idea why someone would sell these?). The 40mm focal length is actually a lot of fun to shoot. On a crop-body, this lens turns into 64mm zoom. I have not used my copy nearly as much as I should ... but its worth holding onto, thats for sure.