TAKO. INTERNET SEIT 1996.
Olympus-OM

[OM] Zuiko & Tokina 35-105mm zooms

Subject: [OM] Zuiko & Tokina 35-105mm zooms
From: Moose <olymoose@xxxxxxxxxxxx>
Date: Wed, 24 Mar 2004 20:29:12 -0800
I've always been curious about the occasional posts suggesting that the 
35-105/3.5-4.5 might have been made by Tokina, presumably a custom 
version of the Tokina SMZ 35-105/3.5-4.3. So I invested (ha, ha) $44 in 
a Tokina to satisfy my curiosity.

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, which I didn't get, is a screw-in design which apparently 
is calculated for use with a filter and uses something like an empty 
filter ring when a filter isn't used to keep the hood in the right 
place. 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.

Which is the better lens? I'll probably never know. I'll try some pics 
with the Tokina, but the chances of carefully matched comparisons are 
slim to none. The zoom action on my Zuiko has always been quite stiff. 
The Tokina is nicer without being in any way loose or liable to creep. 
Build quality? A toss up from external visuals and handling. The CU 
rings are both plastic, but the Tokina doesn't look like it. Which one 
to use on a chrome OM-1? The Tokina 'cause it is a silver nose! (Just a 
joke folks! Easy now!)

A compulsive Moose



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