Question on Sigma 18-200 HSM OS

[izaku]

i'm having some serious lens creep on my sigma 18-200 OS. its like 2 weeks old. what can i do abt it?

 

[animelenie]

i'm currently using this lens with my 400D.
Being one of a travel enthusiast this one maybe the most suitable lens for us (on budget).
landscape, portraiture and zooms are okay.... however, i'm learning bit by bit that "tact" sharpness might not possible especially beyond f/11.