I have a T3i (600d) and a L series 100-400 F4.5 , will a 1.4 extender be manual focus only

[Davesg]

I have a 600D that I use a f4.5 L series 100-400 on.  If I buy a extender 1.4x ii,  can I assume manual focus only?  I had read that a firmware update may change that.....

Thanks

[cicopo]

It will be MF & don't expect a firmware upgrade that changes that.

[Davesg]

Fair enough, I really don't mind the MF, I was just curious.   Thanks