Archived posting to the Leica Users Group, 2001/01/08
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>Jesse Hellman jotted down the following: > >> Regarding Rob's comment that red focuses at a plane different from that >> of other colors, does this mean that there would be little use for an >> apo lens in black and white printing on variable contrast papers, where >> red does not register and the emulsions are sensitive to green and blue? > >I asked this question about a year ago and received a storm of answers from >people who adamantly maintained that APO enlarger lenses provided much >better results that their non-APO counterparts, yet no one was able to >provide a rational explanation as to why this would be the case. > >M. > Martin, Look at this URL: http://www.zeiss.de/de/photo/home_e.nsf/allBySubject/Launch+-+Zeiss-engl+No tesTemplate then click on: Achromat, Apochromat, Superachromat - What is the Difference? This may explain some of what you ask and also addresses the questions of a day or so ago about APO lenses APO lenses in theory at least would be better for taking or enlarging because the various wavelengths would be focused in the same plane. Henry Ambrose Tennessee,USA