EF 100-400L and error 99... only on EOS 20D

[Cadwell]

OK, here's a little poser for you. I have an EF 100-400L IS USM. I've even been known to use it from time to time although to be honest I'm not it's biggest ever fan. There seems to be a little issue with it though.

Because it's not my favourite lens ever and I have other "alternatives" I occasionally lend the 100-400L to other people who are either having trouble with their lens or want to use something a little longer. Two of these people have had occasional ERR 99s when using the 100-400L. They have never had them with other lenses. They both have 20Ds.

I have an EOS 10D and 1D Mk II body. The lens works perfectly with both of those. It also works fine on another friends EOS 10D.

So... is anyone else having this problem or is my 100-400L unique?

[YARRO]

I would advice the 20D owners to clean the lens contacts on the camera with some alcohol.

[Cadwell]

Mmm... possible but both of them have not seen the problem before or since with any other lens. I've not seen the problem with the 100-400L on either of my bodies. Doesn't sound like a dirty contact problem.

[Dave_G]

When I borrowed it for that hour or so it was fine on my 20D - strange.

[GSH]

I don't remember ever seeing an error 99 on my 20D with any lens and certainly not with the 100-400L.

Umm...did these 2 borrowers have 20D Grips with the power & flex issues perhaps ?

[LightRules]

I've never had an error msg with my 1-4IS and my 20D, FWIW. Now my 7-2IS, that has had some quirks.

[Jon]

When the IS on mine packed up it packed up when on both the 20D and the D60. Since it came back I've used it a bunch on the 20D with no problems. You got a wierdie.

[TSmith8779]

I had a similar problem with a 100-400mm I rented when I put it on my 10D. The store I rented it from told me to clean it by using a pencil eraser. I worked for a couple of pictures but then went back to giving me err code.

[Cadwell]

Umm...did these 2 borrowers have 20D Grips with the power & flex issues perhaps ?

Good question. Yes, both of them had grips. However, I know for a fact that one of the grips is a later one which shouldn't have the flex problem ('cos the camera owner had his original grip replaced for precisely that reason). The owner of that camera now has his own lens back (a Sigma 100-300mm f/4EX) so it's a lens of simillar size and weight to the Canon and he doesn't see any issues.

[Cadwell]

When I borrowed it for that hour or so it was fine on my 20D - strange.

Mmm... I'd forgotten you borrowed the lens for a while. Not a problem with every 20D then or perhaps you didn't use it for long enough.

[Cadwell]

When the IS on mine packed up it packed up when on both the 20D and the D60. Since it came back I've used it a bunch on the 20D with no problems. You got a wierdie.

Tell me about it. This lens has already done the IS failure trick, but that got fixed under warranty. It's well out of warranty now.

[blonde]

Glenn,

the first copy i had of the 100-400 gave me that error a bunch of times on my 20D. my second copy has been used daily and never given me any problems at all...

[Chris1le]

My 100-400L is on its way back from Canon right now due to same problem. Hopefully it will work properly. It should be here Friday.:D

[defordphoto]

We use our 100-400 on the 20D all the time. Nary a 1 err99.