It seems like the RF 16 f2.8 would be a very useful lens for APS-C. Compact, tiny, cheap, fast, just over 24mm and no edge vignetting in crop mode.As I said... Maybe(!) for sports shooters (which I'm not!) Aps-c(!!) wide angle lenses don't make sense. But for hiking purposes it does perfectly make sense... At least if you want a good compromise between wide angle, reach and weight!