Yeah the size is the only thing I'm really worried about. But for what you are getting I don't think u can get too much smaller. (it's already an aps-c lens so the Nex one wouldn't be much smaller) I'm planning on it being my walk around all purpose lens as well as a landscape lens. I have a cv 15mm and 18 will serve my purposes well enough. Plus, if u want speed, there's very little wide angle at that speed that are not too much larger.