</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (b.e.wilson @ Sep 17 2002, 04:49 AM)</td></tr><tr><td id='QUOTE'>... being fully corrected (three-color correct) at any distance means they have a better chance at being better corrected at macro distances than lenses that are corrected for two colors at design distances.</td></tr></table><span id='postcolor'>
Well, I&#39;m not sure that follows - an improvement at one point on the scale does not mean that the lens&#39;s performance is improved elsewhere (although it may be so in particular cases).

In general, there are many more aberrations for the lens designer to deal with than just chromatic. For example, I would expect something like a G-Claron to be better at 1:1 than, say, an Apo-Symmar, simply because it is optimized for close range use, and things like coma, spherical aberrations, astigmatism, and field curvature (maybe irrelevant except for copy work) will all be better.

Certainly I prefer my 210mm G-Claron over my 240mm Sironar-N (which is the same as the Apo-Sironar N) for close work. Though perhaps if I had the Sironar S instead I might think differently.

Well, whatever. On the basis that a difference is only a difference if it makes a difference, perhaps this is just splitting hairs.