On 10 Sep 2002 at 20:27, J. C. O'Connell wrote: > Is the APO 125 f2.5 a true macro lens? If it is and it's performance > is better at infinity than close up something is dreadfully wrong. > If it's not a macro lens, then what you say makes sense... > Like I said before, non floating (non- IF) lenses have to be > optimized at a given reproduction ratio, they are not equal > performance at all subject distances. Seems a little fast to be a true > macro...
Yep, lens design sure has moved on since the screw mount era hey? http://www.cosina.co.jp/sllenses/125.html http://www.cosina.co.jp/sllenses/spec.html And for more macro lens MTF graphs see: http://www.zeiss.de/de/photo/home_e.nsf/3187a822cd4605b7c125670900704e24/8c1f493 d03703833c12567a80044f090/$FILE/MakroPlanar_2_8_60_e.pdf http://www.zeiss.de/de/photo/home_e.nsf/3187a822cd4605b7c125670900704e24/f27a4db 51c93e9efc12567a80044efea/$FILE/MakroPlanar_2_8_100_e.pdf Lens resolution is always lost as the magnification is increased. it's just the law of physics. There is an optimum repro-ratio where the edge aberrations are lost (due to the magnification of the image circle) however the resolution is always reduced. Macro lenses most often seem to have better controlled chromatic aberrations probably due to their relatively small diameter lenses, the Lanthar however is a true APO design so the f2.5 speed isn't compromising. The Lanthar kicks most lenses butts (in techo-speak :-) Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html
