How do I buy the right filter?

[robb01]

I would like to buy a couple different filters but am really confused as to the size. I bought one for my 18-55mm lens that was suggested at amazon, but it did not fit.

Anyways, I'm wanting to get some for my new Tamron 18-200mm lens, probably a neutral density and a polarizing filter.

My question is that the filters don't seem to corelate with the lens size, and leaves me with no idea which size to purchase.

Thanks for the help.

 

[Chamelion 6]

On the front of the lens you will see a number next to a symbol looking like a circle with a slash through it. That should be your filter size for that lens.

 

[robb01]

On the front of the lens you will see a number next to a symbol looking like a circle with a slash through it. That should be your filter size for that lens.

TY