i own a Canon XTi and recently when i use my 50mm 1.8 about 80% of the shots instead of shooting an "error 99" message pops up. fortuantely its only with this lens. a few months ago, i dropped it and the plastic on the bottom came off, i was able to re-attach it and it worked fine for awhile. any ideas on what it is? if it isn't worth fixing, i may go ahead and spring for a 50mm 1.4 this owuld be bittersweet, my 50mm 1.8 was my first dslr lens and i've taken some great shots with it, but from what i've heard about the 1.4 i wont miss it much if and when i replace it