Hi--

>Thank you for correcting the mistake. I am sometimes confused about AI and
>AIS, can you explain the differences for me?
"Eugene Chen"

There is little functional difference these days...;-)
The AIS focus ring stays put, and the barrel front
only extends; the diaphragm actuator can be used by
a few bodies to determine the aperture for shutter-priority
and program modes; and the program mode could be shifted
on these bodies depending on FL. No current Nikon body
uses these features. To identify the focus action; the
minimum aperture is orange and the rest are white; and
there is a small "scoop" in the rear chrome flat surface
of the bayonette mount.