In response to a question about his genre winning photo, Onslow said that he used a Lee filters.   Lee as with Cokin are systems where an adapter  is used to allow use of the same filters with lenses of different diameter.  I do not have either system.

I have two questions. The first is perhaps elementary but I don't know the answer. Does the stacking order of the filters matter?

The more important question is about the filter systems. Why systems with adapter rings and the same filters used for each lens?  The first meaningful thought to me is when wanting to use a circular polarizer.  These are not inexpensive. One large enough for the largest diameter lens I would use it with needs only adapters to use the same filter on smaller diameter lenses. That makes sense.

I see the Lee and the Cokin filter holders and filters. Is there a reason to choose one over the other brand?  Lee does make the polarizer and I really do not know if there is a Cokin counterpart.

Plastic also bothers me some in filters. Sure, eyeglasses use high grade plastics and optically work well in eyeglasses. Scratches of plastic bothers me.  I prefer glass for filters..even if the few I own only fit one lens.

Any comments on filter systems like Lee or Cokin will be appreciated and a comment on whether or not stacking order matters.

Richard, if you see this thread, please chime in. You do have the Lee and can perhaps comment on that system.       

Thanks for any input.           TomDart.