Heavy on the 52mm ring size=Nikon.
For my taste, a ring of "extra" material on the front of any lens is protection for both the optic and the threads. Had my share of "dents-n-dings" and found it cheap insurance.
I know on most photo forums I've been on, the question of whether to use a UV filter for protection or not is always a topic of continual debate. I used to always use a UV filter, but these days I've decided to not use them and instead rely on a good lens hood for protection. The exception would be if I was going to shoot an event where flying debris was possible, like an auto race or dirt bike race, etc.
