Thanks for the reply on color meters recently.I'm considering to purchase macro lens for my SINAR 4x5. but cannot decide to go for SINAR lens MACRO SINARON 180( from Rodenstock) or Rodenstock APO MACRO SIRONAR 180 (technical specification ar e the same but for SINAR without 'APO' in their specs ) Can anyone confirm if SI NAR is also APO lens. OR I just forget these two lens and go for SINARON SE lens es for my close up job.For my close up job the average size is between 5 to 15 mm . Your advise and suggestion is very much appreciated Rgds