Sorry in advance for the rookie question... 
I am in the market for a circular polarizing filter for my 28-135mm IS lens.
I know the slim filters are specially made for the "wide angle" lenses, but is it benificial on the above mentioned lens to pay the extra $$$ for the slim filter?
I will be using the lens on my DRebel so with the 1.6x factor the 28mm isn't really a wide angle IMO.

