I have an old Canon XL1 and I noticed that it vignettes, usually when shooting on not well lit places. I left it at a Canon Service Center. It's been three weeks and they still can't explain why that's happening. They can see an error message when attaching the lens to their computer (I don't know how they did it. Probably with a special connector or something) but can't tell exactly what causes the problem. Does that mean it's time to buy a new set of lens? Thanks and God bless.