> an interesting test found > http://members.aol.com/olympusom/lenstests/default.htm > Tokina AT-X 90mm f/2.5 Macro [snip] > Vivitar Series 1 90mm f/2.5 Macro [snip]
Thanks for the info, adphoto. There are differences in the two tests, but I think that the differences (even though they mostly "favor" the VS1 version) are fairly small, and probably could fall within the range of sample-to-sample variance. I still maintain that the VS1 90/2.5 Macro and its 1:1 Macro Adapter are the same design as the Tokina AT-X 90/2.5 and its 1:1 Macro Extender, despite some physical, mechanical, and and cosmetic differences. In fact, Paul has suggested that they were both made by Tokina. Certainly, the details of their optics (as published and as I measured) appear to be identical. I have used both versions myself, and I can't see any significant difference between them. See: VS1 @ 4:1 @ f/8 (without 1:1 Macro Adapter) - http://www.cetussoft.com/pentax/v9025/v9025-41-8.jpg VS1 @ 2:1 @ f/8 (without 1:1 Macro Adapter) - http://www.cetussoft.com/pentax/v9025/v9025-21-8.jpg VS1 @ 1:1 @ f/8 (with 1:1 Macro Adapter) - http://www.cetussoft.com/pentax/v9025/v9025-11-8.jpg AT-X @ 4:1 @ f/8 (without 1:1 Macro Extender) - http://www.cetussoft.com/pentax/x9025/x9025-41-8.jpg AT-X @ 2:1 @ f/8 (without 1:1 Macro Extender) - http://www.cetussoft.com/pentax/x9025/x9025-21-8.jpg AT-X @ 1:1 @ f/8 (with 1:1 Macro Extender) - http://www.cetussoft.com/pentax/x9025/x9025-11-8.jpg Despite the similarities, however, it is not surprising that there would be at least some small differences - after all, even if they were both made by Tokina, the VS1 version was produced basically in the late 1970's, while the AT-X version was a product of the 1980's. Fred
