I've read several threads on this topic, but since each situation is different, I'll post here in the hopes of some thoughtful responses as always. I would like to get a prime lens for my D7000. I'm having trouble deciding between the 50mm and 85mm focal lengths. I am interested in using it primarily for portraits of children and families. I currently use the 18-200mm DX and I'm just not happy with the (lack of) sharpness on that lens. I'm hoping a prime will provide the sharpness I'm looking for. So will a 50mm or 85mm be the better choice? Respectively, I'll be working in the 75 or 127mm length, yes? My concern is the distance from the camera to the subject. I like being about 10-12 feet away (occasionally closer for tighter shots), so as not to make subjects (esp children) uncomfortable with my proximity. Since I need to take into account the 1.5x crop, I'll be standing further away with either of these lenses than with the DX correct?