EF 70-200 f2.8L IS II & Extender 2x III: focus issues at 70mm

Hello,

I bought a second hand 2x Extender III a few months back, and having been using it much since. While testing it with my EF 70-200 f2.8L IS II and my freshly bought 5D mk IV I've just found out that, while everything is fine at 200mm, at 70mm I can't focus at the infinite, only at a few meters, up to 90mm. Then everything works perfectly. With AF or MF, with the 5D or the 6D.

Of course, the 70-200 works perfectly without the Extender, so I suppose the issue comes from the Extender, but what's happening? AFAIK there is no moving part in the Extender. Or maybe that's a normal behaviour I didn't catch before (I usually shoot at 200mm by default with it) ?

Thanks!

I have that exact set-up but have only used the combo maybe twice so far. I'm on the road on business right now, won't be back home until Thursday (10-3). I'll check mine and report back what I find out.

Dan

Well, I just ran a test with my setup (EF 70-200 f/2.8 L IS II, Extender 2x III and 80D body). No issues in focusing at infinity at any zoom setting from 70mm to 200mm. I made several AF tests at various distances from about 50ft. to maybe 1/2 mile or so. No problems at all.

Not sure what might be causing your issue. Maybe have someone check it out.

Dan

Thanks! I'll bring it to a shop, weird...