70-200mm problem

<p>My 70-200mm f2.8 is faulty. Autofocus works at best sporadically in horizontal mode but perfectly in vertical - with either set of controls. This is common with three different camera bodies so it's a lens problem. Does this ring bells with anyone ? Sometimes there is an obvious simple solution before sending off to hospital.</p>

<p>is your 3m - 1.5m autofocus switch on the lens OK?</p>

<p>(3m setting improves distant object AF)</p>

<p>I don't recall seeing this problem mentioned here before, so it's probably not a common issue. Try moving the MF/AF switch back and forth several times to ensure it is making good contact.</p>

<p>Derek, I've read of this problem before. I don't remember which lens, but it was probably a Canon. I never read any follow-up as to what caused the problem. My guess would be a faulty internal connection. Either that, or perhaps you need to clean the mount's electrical contacts, both on the lens and on the camera.</p>

<p>Thanks good people. Been down the contact cleaning road already to no effect. Got an answer from an English press photographer who had similar which turned out to be due to a faulty (or dead) IS. I rarely use same but when I tested it sounded rough so perhaps. It's off to canon today - I shall update for future reference when I hear their verdict. Cheers</p>

<p>Early in the 70-200/2.8L IS USM's existence, there was indeed a problem with IS units which had a habit of dying prematurely. I don't recall the details, including when it was that they started shipping lenses with an improved IS unit, but I'm pretty sure it was within the first couple of years that this lens was on the market.</p>

 

<p>From your description, it sounds like something loose on the inside, likely a connector, maybe a hairline crack in a circuit board or internal wire. Anyway, Canon should be able to sort it out easily enough.</p>

<p>Lens repaired by Canon UK - fixed price repair - £127 ish. Repair note not too helpful: Repaired zoom system: Repaired barrel: set to standard: replaced rubber mount. A brief test in the back yard indicates a working lens. Might have been quicker had they used Royal Mail rather than UPS - UPS don't get out of bed on a Saturday where I live: the postman calls every day and when he's gone past you are free to roam - few things more aggravating than sitting in waiting for a courier who doesn't come. Anyhow apart from that a pleasant surprise given past history of Canon "repairs"</p>