inexpensive one-element diopters on the market and they are not
worth anything but making your good lenses look crappy. I have all
the good diopters and never use them. Almost never. Occasionally
I fool myself into experimenting just to remind myself why I don’t
use them.
Polarizing Filter
Useful for darkening skies, reflections on water or leaves, etc. I
have them but seldom if ever use them because I am doing close-
up and macro, so not sky, shiny tree leaves, open water, etc.