I dropped my 18-105 Nikon kitlens. The image produced after that is like this. Shaky with soft edges. But the focusing mechanism is still running with the regular focusing sound. What could be the problem? Is it expensive to repair? Will the warranty cover it? I still got mine under warranty.
It seems likely that some of the internal elements are out of alignment. An internal element got knocked loose from its precise location.
I won't guess at the exact cost, but I expect repair would be cheaper than the cost of a new lens — but maybe not less than the cost of a used one.
Unfortunately for you, though, this isn't a defect in workmanship, and so not covered by the warranty. Warranties aren't insurance against something going wrong, but rather a promise that the item itself was made to a reasonable standard of quality. If the lens came to you in this condition, or developed this flaw in normal use, that would be a warranty issue. Or, if they promised that the lens could withstand a certain amount of shock but it didn't — but this lens is certainly not sold as drop-proof.
If you're extremely lucky, they might do it anyway, but don't count on it.