On Fri, 22 Nov 2002 04:48:56 GMT, Andrew wrote:
>On Thu, 21 Nov 2002 16:32:27 GMT, d_ruether@hotmail.com (Neuman - Ruether)
>wrote:
>>On Wed, 20 Nov 2002 21:00:14 GMT, Andrew
>> wrote:

>>[...]
>>>Being an Ai lens, mechanically
>>>it was excellent. Build quality went noticeably downhill ever since
>>>the Ai-S series arrived.
>>>Andrew

>>?????????????
>>I would say, "after the AIS series"... The AIS MF
>>were the best-made of all (except for the "E"
>>versions), and tend to have the smoothest focus
>>with the least wear problems (two adjustable
>>hold-back pins are used in the focus-mechanism,
>>instead of one as in the AI lenses, helping to
>>keep things better-centered during focus, and
>>more easily adjusted after helical wear). The
>>aperture mechanism of the AIS lenses is also
>>improved, permitting use of the actuator lever
>>by the camera to adjust the stop in auto modes
>>with reasonable precision. I can think of no way
>>in which the AI lenses were preferable

>I used to have 3 Ai-S lenses, none of which had the build quailty of
>my 2 other Ai lenses, let alone my 2 pre-Ai models. The Ai-S lenses
>were noticeably flimsier and lighter when compared with the earlier
>models, with a significantly shorter focus throw and consequently much
>less useable DOF scales.

This last is a design issue, not a construction
one, and I partially agree with this - though in
practice, I think the AIS "throw" made good focus
easier (one didn't need to "crank" high-DOF lenses
excessively to hit good focus - and the "throw"
was adjusted fairly well to the FL, even with
zooms, for easiest MF). The loss of good DOF info
was noticeable, though (though that info was
generally not very useful since it was too
"symetrical" and "optimistic" for critical use
(as is most on-lens DOF info...). I never noticed
much weight difference, though...

>(Not to mention obviously cheapened
>(plastic?) "silver ring" and flimsy Ai prong.)

The rings on all but a couple of late AIS lenses
were all metal, and the prong was "opened-up" to
better light the aperture ring for the direct
optical readout of the aperture used - an
improvement...

>The aperture mechanism
>might have been slightly improved but actually one does not need an
>Ai-S lens to use programmed or shutter priority modes on the FA and/or
>FG, according to at least some users.

This is (almost) true. The AI lenses were useable
on bodies that could use the "S" information, and
*some* of these had an "exposure preview" function
that checked the stopped-down aperture error before
exposure and made shutter-speed compensations (FA).
The program-switch for longer FL lenses did not
work with non-"S" lenses, though, and exposure
errors could occur with some bodies with AI
lenses in some auto modes...
Also, with the switch to AIS from AI, a few lenses
were optically improved. The 28mm f2.8 is the most
notable example...

>Here's a great page for visual comparson of pre-Ai/Ai/Ai-S/AF lenses:
>http://home.aut.ac.nz/staff/rvink/nikon.html

Yes, thanks. I will add it to the Nikkor evaluation
list, at: www.David-Ruether-Photography.com/slemn.html.