I wonder if the red filter Ansel Adams used for Monolith: The Face of Half Dome was brass and multi-coated? Remember the good old days when you went into a camera store and had a choice between Hoya, Tiffen, and an off-brand like Prinz, and without consulting the Oracle of Delphi you picked one, and then just went about making photos without all the angst and handwringing? I swear the internet has made us all neurotic. You know you are in trouble when you meet another photographer and sort of nonchalantly glance down at his camera and take note of the filter brand he uses, and then, if you use the same brand, you give him the secret handshake. Wait...I just checked and a Leica E39 UV filter runs $145. I have no idea what the "E" stands for. Probably "expensive".