I'm trying to decide between a 50mm F1.4 AF-D or AF-S lens for use on my F6. I'm perfectly happy with my older AF-D lenses, but now I'm wondering if the newer S versions might be better. It seems to have better AF, but I'm used to having an aperture ring even though I rarely shoot in manual mode. I value light weight, and the D lens is almost 2 oz lighter. And the S takes 58mm filters, while the D takes 52mm like my 24mm AF-D. Also, the S seems to have slightly more distortion (barrel and linear) even though this might hardly be noticeable. The S lens is somewhat more expensive. All in all, is the S lens a better choice?