70-200 2.8 L IS I weird AF and IS behaviour torwards 70mm

Hi all,

I have had a quite weird issue with my 70-200 2.8 L IS mark I on AF and IS.

When at 200mm, the AF locks rocket fast and IS would stabilize my shots during a mag 10 earthquake. But as soon as I zoom out, until 70mm where it's the worst, the AF takes a while to get to focus point and the IS rocks and roll around the subject. If I deactivate the IS, there is still the issue with the AF.

It leads to funny points, where I would get sharper results at 70 without the IS that with it, and the lens getting crazy in AI Servo (It locks on the subject, but the IS moves the frame so it tries to focus on the background but when it has locked, the IS had already moved back to the subject and so on...)

What I can say is the two problems seem to be linked, as they appear with the same progressivity when zooming out but the fact that the AF still bugs when the IS is off...

So I have looked online for similar reports but without any success. Does anybody had the same issue with it? I know the IS has some rolling parts that need to be changed after a while, if it can explain the problem with the IS, would it also solve the problem with AF?

Any thing else? Yes... it is not camera-related as appears with my 6D, my 1v and a few other bodies I had in hands.

I know by the date code that this lens is quite a early one (2001). I bought it as a non working bargain and had the zoom key replaced along with AF calibrated. I know that was risky and that would frustrate people who take care buying second hand gear that is in perfect condition, but for far less that the usual price including the repair, I got myself great lens that works really well in most of the situations. It might just need a bit of extra care.

Thanks

V0l

That isn't normal behavior. I had something similar happen with my old 70-200 f/2.8 (non-IS) or 70-200 f/2.8 IS version 1 (I've owned them all and I forget which one did it). It needed repair.

But if you are satisfied with manual focus, you may be fine.

Thanks Craig.

Do you, by chance, remember what needed to be changed/fixed?

Thanks again.

The verdict came...

The IS module have to be changed for a price of 550€ (the part itself is 300), including the button plate on which the AF/MF switch has failed. And yet, the repair shop made me a discount on the hand work, billing me only two hours.

After the 300 for changing the zoom key, this lens is starting to get expensive to maintain in a working order...

Viticol wrote:

Thanks Craig.

Do you, by chance, remember what needed to be changed/fixed?

Thanks again.

No, sorry. I think they replaced a circuit board, but it's been over a decade ago and I can't remember breakfast.