Nikon is going to release AF-S 50mm f/1.4 to replace the older AF 50mm f/1.4D. Can someone enlighten me what the advantages of USM/SWM are? I know that the older one can't AF in Nikon D40/D60, but from the reaction on the internet, it seems there are a lot of people expecting/waiting for this AF-S version. I'm sure some of the people are not D40/D60 user. Why are non-D40/D60 users so happy with AF-S version?
Does USM focus faster and/or quieter than traditional motor? Is USM more energy efficient?
I've heard that the AF speed of the USM version of Tamron 17-50mm f/2.8 (Nikon mount) is slower than the older non-USM version. Except Tamron 17-50mm f/2.8, is there anyother case which compares USM and non-USM?
Does USM focus faster and/or quieter than traditional motor? Is USM more energy efficient?
I've heard that the AF speed of the USM version of Tamron 17-50mm f/2.8 (Nikon mount) is slower than the older non-USM version. Except Tamron 17-50mm f/2.8, is there anyother case which compares USM and non-USM?