Archived posting to the Leica Users Group, 2005/02/11
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Here in the LUG we have referred to completed lenses as "glass" ( I think I started that bad habit). We have also referred to APO lenses. See description in heavily technical scientific dictionaries if you want to figure out the techie stuff. The reference to a single piece of glass as APO ( or Apochromatic) can be correct, but in all the references I have seen, it refers not to a glass element, but rather to an optical chain ( which may be a single element, but may have and usually does have more elements.) It is a complete optical chain. I think Frank D is right. Referring to an optical component as APO is incorrect. It does not mean it was not done, but it is incorrect. Frank Filippone red735i@earthlink.net Please point me in the direction of some explanation of what "APO" glass is then, if you know a url. I have heard of APO as an overall complete lens design specification many times but I have no knowledge that there is a particular APO glass. Frank