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[OM] Re: ?? Mid-tele zoom w/49mm filters??

Subject: [OM] Re: ?? Mid-tele zoom w/49mm filters??
From: "John A. Lind" <jalind@xxxxxxxxxxxxx>
Date: Sat, 16 Apr 2005 23:04:27 -0500
At 05:23 PM 4/16/2005, Moose wrote:

>Seems a little unfair.

Perhaps, but my assessment of the reasons Olympus made the 75-150/4 are 
different.  The 80-200/2.8 Tamron is (IMHO) pro grade.  The 75-150/4 was 
not, and was never intended to be, for rational business reasons.  It is 
tied to when they (the Oly and Tamron) were designed though.

In the early 1970's when the 75-150/4 was designed, there were no pro grade 
zoom lenses to speak of.  The pros using 35mm small format pretty much 
snobbishly snubbed the idea of using a zoom lens and favored the 
traditional battery of primes.  The situation had changed when the Tamron 
was created a decade later; zooms had gained greater acceptance among the 
pro community and there was a greater pro market for them.  I believe the 
design capabilities for lenses such as the Tamron were present in the early 
'70's; lens design and glass chemistry had advanced considerably in the 
nearly 30 years following WWII.  The market wasn't ready for them though; a 
situation similar to Edison's voting machine.  One limitation _may_ have 
been zoom lens focal length range . . . 2X was common in the early '70's . 
. . the sheer mass of ray path calculations to design one with greater 
range (and hence greater complexity) might have been substantially more 
costly . . . but I don't believe it was impossible or even infeasible if 
the cost of doing so could be justified (the Tamron is 2.5X).

The non-recurring engineering effort for a lens like the Tamron would have 
taken more time the early '70's, but lens design wasn't without computer 
tools either.  It would have been done using small mainframes.  Low 
dispersion and very high index glasses also existed, and had been used in 
optics since the late 1800's, but they would have used different Rare Earth 
Elements in the glass chemistry such as Thorium (IIRC, Th is what was used 
in the 55/1.2; very likely the Tamron uses Lanthanum).  Multi-coating was 
also well-known and thoroughly understood, but the manufacturing cost in 
making MC lenses was much higher.

[Note:  Thorium is not a "true" REE, but an Actinide.  However it is 
commonly included in lists of REE's due to its similar properties.]

In conclusion . . .
I don't believe it was incapability that prevented lenses like the Tamron 
from appearing in the early 1970's.  The "how to" was well understood.  It 
was complete lack of a rational "business case" that could justify doing 
it; a combination of high cost and lack of pro market willing to pay for 
it.  IOW, Olympus *could* have made something like the Tamron had they 
wanted to.  There were rational reasons not to.  I believe their design 
team knew they were making trade-offs with what was technically feasible to 
meet overall system concept goals and create a marketable product.  We do 
this all the time where I work; conscious, justifiable trade-offs of 
technical performance to meet other important goals.  Doesn't stop us from 
benchmarking that against the technically BOB (best of the best) to see how 
much trade-off we're making.

With the OM system in particular, compact size and lighter weight was given 
higher priority than with other systems (notably Nikon).  As a result, 
Olympus shied away from creating big, heavy glass.  I believe that is the 
reason for the dearth of fast zooms in the OM lens line.  The only true 
"fast" zoom was the 35-80/2.8 and it came very late (IMVHO, too late).  By 
the time of the Tamron in the 1980's, the pro market for zoom lenses 
demanded fast, constant aperture glass.  If compact size and weight were 
given a priority, the zooms would have to be slower.  Therefore a solid pro 
market for the OM zooms wouldn't exist.  Designing a slower zoom that met 
system concept size/weight goals with pro grade optical performance and pro 
grade price point wasn't rational from a business perspective.  The 
circular nature of this tended to feed itself.  IMHO the OM system never 
did contain a zoom lens for the "pro market," save the 38-80/2.8 that was 
introduced "a day late and a dollar short."  Companies like Tamron filled 
the OM void in this area when the market for them emerged.

That's why I don't feel pangs of guilt using the Tamron as a benchmark for 
optical performance.

The above conclusions are _opinion_ and should be viewed as such.

-- John Lind

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