New to Superzooms, 500 f/4 52mm, Screw In or Gel Filter Holder?

Hi: First up, thanks to everyone who helped me decide on a camera/lens upgrade recently. I did heed the advice on lens, Z1 ballhead, SideKick, and assorted Wimberley parts.


I recently purchased the Canon 500 lens for my 5d/II. I've tried sorting though this, but I still don't know the advantages/disadvantages to each option.


Thereare separate Canon drop in filter holders for 52mm screw in or gel filters. I'm clueless as to what a gel filter even looks like, much less advanges or disadvantages (I only recently even heard about drop in filters). What I'd like to do is to use a polarizing filter on bright days. I can see this is going to be much more expensive than the 77mm polarizers I've been using so would like to purchase right the first time.


So, what are the reasons I should go with a gel vs screw in filter adaptor, or better yet, does the filter holder that came with the lens (protect glass?) adapt to a polarizer?


Again, thanks to all. gary