anyone with a canon 70 300

[kevin0410]

hi,

i have a canon 70-300 lens with a problem.
Something has come loose inside, the is jumps like crazy when engaging.

What i would like to know...
Is the rear element supposed to move in and out when the lens is zoomed in and out?

Thanks

kevin

 

[redondo]

Rear elements are supposed to move in and out.

Something has come loose inside, the is jumps like crazy when engaging.

bit more detailed description could be more useful.