On Fri, 6 Jan 2006, Don Williams wrote:
The awful chromatic aberration of an very expensive Schneider 360mm telephoto I had for many years made me very much aware of the problem. But a few years ago I got a Sigma 5.6/400 APO and the images are very clean. That was my reasoning.
From what I recall reading here, the Sigma in q needs more than APO to
be used as you go towards its long end. Kostas
