Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 beta 3/9/83; site sdcrdcf.UUCP Path: utzoo!linus!philabs!sdcsvax!sdcrdcf!brad From: brad@sdcrdcf.UUCP Newsgroups: net.rec.photo Subject: Re: Filters Message-ID: <330@sdcrdcf.UUCP> Date: Thu, 16-Jun-83 09:21:58 EDT Article-I.D.: sdcrdcf.330 Posted: Thu Jun 16 09:21:58 1983 Date-Received: Sun, 19-Jun-83 04:15:40 EDT References: <359@ihuxw.UUCP> Reply-To: brad@sdcrdcf.UUCP (Brad Spear) Organization: System Development Corporation--a Burroughs Company Lines: 23 In reference to the question about Skylight 1A and UV filters: Both the Skylight 1A and UV filter some blue-violet-ultraviolet. The UV is specifically used for the Ultra-Violet, while the 1A also 'warms' the scene somewhat. If you look closely at each, the 1A is 'pink', while the UV is visibly clear. (It wouldn't be if you could see UV) The reason for filtering UV is because the film in your camera is not sensative to the same range as your eye, it can 'see' the UV, which will make your photographs come out bluer than normal. This is normally not a problem, but can be, especially at midday and at high altitudes. In these cases, sunlight is considered 'cool', because it consists of a high percentage of 'blue' light, as opposed to morning, evening or low altitudes where the light has less blue and more 'red', thus being 'warmer'. They are both also used as lens protectors, since they pass what you see relatively unchanged (except 1A is slightly redder) and are much cheaper than a lens. I don't want the warming of a 1A usually, so all my lenses are fronted with a UV. The distortion of a good quality filter is usually negligible. Brad Spear sdcrdcf!brad