Canon Ef 70-200 Repair Manual
Canon 70-300 DO IS USM Repair Manual - Canon Ef 70-300 Mm F/4.5-5. Epson Fx 2190 Driver. 6 Do Is question. Canon EF 70-200mm f4 L IS Manual Focus Fixed in 5 Minute Repair. See this video which has nearly 4,000 hits from unsatisfied Canon users looking for a repair. 12 Years with a Canon 70-200 f4.
Doing a little checking: a used 70-200 F4 L in decent condition can be had for around $600. While it's certainly possible that a repair would be $300, it probably won't be that much.
Not sure about your options, but my local shop has some kind of deal with Canon where they ship it to Canon, get an estimate, and I can then decide whether I want to go ahead with it. If I decide not to, all I pay is the shipping (usually around $35). If I do, it's just the cost of the repair.
Might be worth looking into. Canon C300 Sample Footage Canon here. – Jun 12 '12 at 18:30.