Well, I have never used a 18-200, but I do have a 24- 105 L series that got a broken AF cable inside. I did send that in. $300 later, I got it back. I though that was pretty expensive for that lens. It got a crack in the barrel now, and I don’t think that I will get it repaired because of the price.
I don’t know what a 18-200 is worth, but you may be better off going lens shopping 🙂 I once took a lens apart- it might be a easy fix. You could try to take the rubber of the focus ring grip and see if there is any thing obvious wrong. Other wise, you will end up tearing the whole thing apart. It’s not too complex, but there is a risk to it. You could look at the Lensrentals blog- they recently tore down a 70-200 to remove a fly, of all things!
Let us know what you find!
