Talk:Filter
| This is the discussion page for Filter. Click here to start a new topic.
|
Regarding this edit, can you cite a source for the statement "most lenses already include UV coating"? Most? Glass itself absorbs shorter UV wavelengths (particularly higher-index types— see pgs. 4-5) but that is not a coating. --Vox 14:02, 17 March 2012 (PDT)
- Quite correctly you state that glass absorbs UV anyway, somewhere I have read mention of a layer (lens cement I think) formulated to absorb UV. In any case, the use of a UV filter is probably unnecessary.
What do you think about merging the neutral density filter article with this one? There doesn't seem to be a need for both --DesmondW 04:03, 22 April 2012 (PDT)
- Well, there are a number of pages that do (or might) link specifically to neutral density filter, so it seems preferable to keep it as a separate entity (linking to an anchor within an article can be "fragile," because any tiny change to that subhead text breaks it). The use of ND sheets as a light-adjusting element in exposure meters is also conceptually distinct from the photographic uses of other filters. --Vox 09:37, 22 April 2012 (PDT)
- It all seems the same to me, and a redirect cannot be broken. I leave it up to you --DesmondW 04:18, 24 April 2012 (PDT)
- My experience is that older manual lenses did not have coatings to absorb UV. While the glass or cement may have absorbed some, it wasn't as much of a concern as it is today. Modern sensors are much more sensitive to UV light than film. Even coated lenses from film days don't always provide much help with UV. You can see the difference pretty clearly by mounting older telephotos on digital cameras. Shoot a high contrast subject with the lens wide open. You'll see really bad purple fringing if the lens is not UV coated. This frequently gets written off as bad CA due to a bad quality lens but it can usually be corrected by the addition of a UV filter. Here's an example with a Soligor "multi-coated" 300m lens from the 1970s. If we have a "purple fringing" article somewhere (maybe on a lens defect page), these pics would be good examples. Steevithak 08:08, 24 April 2012 (PDT)
- Good points and a great example. I will incorporate these (poor UV absorbtion in older lenses; greater UV sensivity of digital sensors) unless someone else beats me to it--DesmondW 08:12, 25 April 2012 (PDT)
