Hi guys. I have a 35-70MM Quantaray SLR lens. It has been working flawlessly as long as I have had it. Recently it's started to stick when I try to manually focus the lens. Such as, when rotating from 35mm to 70mm, it will stick just before 70mm and will not go any further. When I try to go back to 30mm, it stops just before 30mm. It takes a few more slides back and fourth to get it to go to 30mm/70mm. This is also the case with the secondary focus but it is much more difficult. This lense is practically always on the camera, has never been dropped, has never been in intense heat/cold or anything that could possibly damage it. I have not forced it roughly either but it will just not move smoothly as it used to for some reason. Any feedback is much appreciated.