diddo what bbaslaga said.. my 24-105 does that also... I think most lenses that extend does this... All my L's that dont extend seem fine... The 70-300L extends, however they put a zoom lock on the lens but it's locked at the 70 position... I'd personally like it if they can make it so when it locks, it locks whereever you have it set at, but i may be asking for too much...