Archived posting to the Leica Users Group, 1998/06/05
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>and what does "APO" mean ? APO is short for apochromatic which should mean that a point of white light entering the lens is focussed on the film as a point of white light and not a point of white light with colored edges where the light has been bent differently according to its frequency. In practice it means (for most lenses) that the white dot has much less color fringing in an APO lens than in the same non-APO lens. From what I recall about R lenses there are a couple of APOs from Leica that reputedly are truly apochromatic...one of the R people can undoubtedly shed some light on that point. - -Charlie