The Canon "L" lenses are truly worth it when you want the best image possible . . . and you'll notice that the images will really "pop."
Filters? When one puts a cheap filter glass onto a top flight "L" lens the filter will typically degrade the image and it won't "pop" like it did without the filter.
What to do? Well . . . I didn't invest my hard-earned money on "L" lenses just to put a cheap filter over the end of it. If I want that effect I just put my "kit" lens on the camera for casual shots.
Ironically, the only lens I have that has a filter on it . . . is my kit lens! That's the one that might get fingerprints on the glass from the 2 year old grandkids! Still . . . when I'm serious about shooting the "grands" I'll be using an "L" lens when possible.
