On Thu, 19 Nov 1998 01:05:28 +0100, Bjørn Rørslett wrote:

> [.......] On the other hand, the AI 200 mm
>f/4 with 5 elements is superb. High contrast and tack sharp even wide
>open. Serial no starts at 710 xxx. The same lens also briefly existed as
>a non-AI lens (s.n. 670 xxx and up). This 5-element design was followed
>by the AIS version (from sn. 900 xxx) which had a slimmer barrel but
>otherwise was optically unchanged. All 5-element variants are great for
>close-up photography in conjunction with an extension ring or a 4T
>close-up lens.

Great indeed...! ;-)
With standard macro lenses plus achromats, converters and/or tubes
I could not get much above 2X with first-class sharpness. With
the Nikkor compact-version 200mm f4 (non-macro) combined with the
Sigma achromat (the one supplied with the Sigma 90mm f2.8 macro)
and tubes or a converter, I can get to 3X+ sharply (still with an
auto diaphragm). BTW some samples are on my web page under
"photographs", then "Bugs"...