Canon 100-400mm Locking ring loose!

[silverfoxcc]

Just below the 'manual focussing ring' there is a ring that 'locks' the lens zoom position.
Only now it doesn't

Is there a DIY fix or does it need to go back to Canons repair dept

[bcr5784]

I'd be surprized if there was a DIY fix. Since you say it is "loose" you must know it only works when the lens is fully retracted at 100mm (and isn't loose otherwise). That said mine doesn't (yet) need a lock switch - it doesn't extend under gravity - but it is pretty new so that might change.

Edited by bcr5784 on Thursday 23 July 17:27

[DIW35]

I don't know if it's meant to be an actual locking ring or just an adjustable friction ring, though I guess if you turn the friction up to max it effectively worls as a lock. No idea how it works internally, but I'd be surprised if you could fix it yourself unless you are happy to dismantle the lens.

[bcr5784]

DIW35 said:

I don't know if it's meant to be an actual locking ring or just an adjustable friction ring, though I guess if you turn the friction up to max it effectively worls as a lock. No idea how it works internally, but I'd be surprised if you could fix it yourself unless you are happy to dismantle the lens.

I'm pretty certain from the feel of it that it is NOT a friction mechanism, rather a mechanical interlocking switch which only functions when the lens is in the fully retracted (100mm) position..