Just bought a vintage Canon FD 24mm S.S.C. lens for my Panasonic G7. I am waiting on a B+W ND filter for the lens to do some video work. I am looking at the front element of the lens and notice that it is convex and it seems that the filter might hit the element when screwed down. I have seen this same lens for sale with filters so it seems that folks use them , but man, looking at the front of this lens, it seems the filter will come REAL close to the lens element. I have read some horror stories from filters scratching the lens of Canon zooms. So, I am just being cautious and would love to get some feedback from anyone who might have insight. I guess I will find out when the filter arrives, but from the looks of this lens, I am more than half scared to even thread it on. Thanks in advance.