Maybe it isn't made by Tokina, maybe Cosina or Kiron, or Sigma or Tamron?
--
Chris Crawford
Fine Art Photography
Fort Wayne, Indiana
260-747-5101
http://www.chriscrawfordphoto.com My portfolio
http://blog.chriscrawfordphoto.com My latest work!
On 5/29/09 4:40 PM, "Moose" <olymoose@xxxxxxxxx> wrote:
> John Hermanson wrote:
>> At least the plate has 3 screws holding it all together when you drop it back
>> in. That is what tipped me off that the 35-105 zoom is definitely not
>> Olympus built. The only screws holding all the blade parts in are
>> the 3-4 screws that hold the blade assembly into the barrel. You have to ...
>>
>
> I'm certainly in no position to argue with your expertise. I did make a
> modest effort (i.e. no tear-downs) to check the persistent rumor that it
> was a version of the similar spec Tokina. Here's my list of comparison
> points:
>
> ------------------------------------------------------------------
> "I can see where someone could at a casual look think they might be the
> same underneath. They are very similar in size, weight and overall
> appearance except for very different rubber focus/zoom ring covers. On
> closer inspection, I note the following:
>
> 1. Coating reflections are different colors, indicating different
> coating design/technology, and size/depths, indicating different
> internal element shape/configuration.
>
> 2. Front mounting of the front element of the zooming group is slightly
> different.
>
> 3. The Zuiko focusing helicoid takes considerably less rotation of the
> focus/zoom ring to get to its
> minimum of 1.5m and than the Tokina takes to go to its minimum of 1.6m
>
> 4. Zoom ring travel from 35-105mm is 20.8mm on the Zuik and 20.6mm on
> the Tokina.
>
> 5. Although the close focus mechanism uses the same principle of acting
> as an extension tube, the ring moves in opposite directions on the 2
> lenses, locks into CU position on the Zuiko, but not on the Tokina and
> has a different extension length, 6.6mm on the Zuiko and 8.3mm on the
> Tokina.
>
> 6. Both have 6 blade diaphrams that point their fingers clockwise, but
> they are mounted opposite ways, with the fingers on the Zuiko toward the
> front and the Tokina to the back. The Zuiko hexagon is also a bit more
> symmetrical and consistent as it is stopped down.
>
> 7. The rear element of the Tokina is considerably larger and mounted
> into its cell differently than the Zuiko.
>
> 8. The finish of the visible part of the mount is classic Oly matte on
> the Zuiko and shiny on the Tokina.
>
> 9. The mechanisms that convey aperture setting to the pin on the rear
> and operate the diaphram from the other pin on the rear are quite
> different designs, with the Zuiko using the same basic design as in
> other Zuikos I've had apart.
>
> 10. The Zuiko has 16 elements in 12 groups and the Tokina has 16 in 13.
>
> 11. Ths Zuiko is styled pretty much like the 70-150 and 35-70/3.6 &
> 35.-4.5 except fot the close-up ring, which isn't on those zooms, but it
> is in the same relative position as the zoom rings on those 2 touch
> models. I assume the otherwise odd design of the CU ring with the groove
> around the middle is to differentiate it from the zoom rings on the
> others. The Tokina is styled just like the other Tokina zooms I have.
> Finish of the body surfaces is very similar.
>
> 12. The nose of the Tokina in front of the zoom ring is much shorter
> than on the Zuiko, so the Oly hood doesn't clamp on as securely. The
> Tokina hood is also a clamp-on design but is calculated for use with a
> filter and uses something like an empty filter ring for the hood to
> clamp onto when a filter isn't. The Oly solution of a clamp on hood that
> doesn't interfere with filter use is much nicer.
>
> My conclusion? It is extremely unlikely that the Zuiko is an adaptation
> of the Tokina. There are just too many differences that wouldn't make
> sense if it were, especially things like reversing and changing the
> length of travel of the CU helicoid, changing the pitch of the focusing
> helicoid and changing the internal design of the auto aperture
> mechanisms. It also really does appear to me from the reflections that
> the internal elements differ quite a bit in surface curvatures and/or
> locations."
>
> Moose
--
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/
|