Last night I received some compensation to make up for an eBay item that had been slightly less than "as described." Said compensation included a circular polarizer filter for the lens that I'm using on my Ricoh manual SLR. I've been meaning to buy and try a 25A filter for this lens, since all the film I shoot is black and white, but after reading up on the polarizer it seems that their functions overlap somewhat (yes, I know that the red filter is for color and the polarizer polarizes). Basically, I am looking to darken my skies and bring out contrast in bright landscape scenes. As I understand it, the red filter will increase contrast and darken the sky, and the polarizer will darken the sky and reduce glare, which will apparently increase contrast as well. I plan on trying both, but would anyone care to comment on the difference between the two for this type of shooting?