With the popularity of mirrorless cameras from Sony, Fuji, Panasonic among others, more and more Canon users are either changing systems or wanting to try these new cameras. That in turn, is making adapting lenses more popular than ever, especially as autofocus performance continues to improve and includes many native features like Continous Eye AF (in the case of Sony cameras).
While I was never a Canon DSLR owner, I have purchased Canon EF lenses before to use with my Sony... more