On 28 Nov 2002 at 13:25, andre wrote: > I noticed that the IR (infra-red) mark on Takumar lenses were > generally closer to infinity with newer designs (50/1.4 8-elements > being an exception). Does it mean that a lens with an IR mark closer > to infinity is better corrected for axial chromatic aberration than > one with an IR mark farther from infinity? Can we somewhat judge the > amount of correction looking at the position of the IR mark?
Hi Andre, It could be but it's hardly conclusive, consider firstly that you don't know what wave-length the IR mark on each lens is calibrated for. Possibly earlier lenses were calibrated for shorter IR wave-lengths? Leica lenses don't feature IR marks for this very reason, to the uninformed it can be quite misleading. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html
