on 2/10/03 6:45 PM, Bill Pearce at bspearce@xxxxxxxxxxxxx wrote:
> With zooms, the internal mechanism may preclude an aperture ring at the
> front of the lens. This would make the 90/2 all the more unusual. I, too,
> suspect a new generation of designers, all taking aim at the master.
>
> Bill Pearce
Most of the zooms and some of the telephoto lenses have the aperture ring at
the camera end due to the additional mechanical mechanisms inside which make
it harder to control the aperture from the front. I think the 90/2.0 has a
double-helical focus mechanism, which might also have made Olympus decide to
put the aperture ring at the camera end... probably simpler to keep it
linked up without complicated interleaving pins and slotted arms, etc.
Actually that's what are inside most of the lenses, to accomodate the
movement of the focus mount, but more movements are involved with zooms
hence the apertures at the back end.
--
Jim Brokaw
OM-'s of all sorts, and no OM-oney...
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|