Archived posting to the Leica Users Group, 1997/07/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Willem-Jan Markerink wrote: >I might have asked this before, but don't think I saw a confirmation: >Does the 70-180 still need focus correction for infrared film, or is >it a true APO in this respect too, just like all other Leica APO primes? >Does it show a red dot on the DOF scale, or is this mentioned in the >manual? Apo correction does not imply that refocussing for infrared is superfluous. It is unlikely that even if the 70-180 were a true apochromat for all focal lengths, one of the three correction points would lie in the infrared; and besides, which wavelength in the infrared is it you want the best correction for - it extends quite a way. It might need very little refocussing for most infrared photography, but the Apo designation goes not guarantee it. * Henning J. Wulff /|\ Wulff Photography & Design /###\ henningw@archiphoto.com |[ ]| http://www.archiphoto.com