OK, I have two B+W IR filters. The 092 (89B) and the 093 (87C). The 093 filter is supposed to block the entire visible spectrum. So - why can I see through it? Sometimes it's hard to tell these filters apart with a quick glance, so I hold them up to some light. The 092 filter does not block all visible light, so you can see through it OK in bright light. The 093 filter should be blocking all visible light, so it still looks black; but - I can see the sun through it. If it's blocking all visible light, how is it that the sun is visible to the eye through it? If it really did block all visible light I should not be able to see anything through it, including the sun, right? And I know about the dangers of looking at the sun, I'm just talking about a brief glance through a very dark filter here. One more question, just so I don't have to start a new thread... The UV filters (not that kind) are looking pretty interesting too. I'm talking about the filters that block everything except for UV light. These. Does anybody know what the sensitivity of the 350D (or any other body) is to UV light? The glass in my lenses will absorb some of the light too (I think I remember reading that quartz lenses are best for this...$$$$), right? I guess what I'm asking is, is it even worth trying?