Story of a 35mm: Nikon Canon Zeiss

[flavio81]

This article has a number of things that are basically true but one has to discount everything by 50% for the particular company advocacy, ie GREATEST OPTICAL MANUFACTURER EVER puffery. This is not to criticize your conclusions, merely the biases of the article.

Most optical glass manufacturers are capable of making a wide array of glasses to suit lens designs for all but the most exotic lenses (excluding aspheric and molded/machined designs which are another realm of manufacturing difficulties). One cool thing is that Ohara gives us mortals a rough idea of what each of their glasses costs. Have a look at their chart: https://www.oharacorp.com/pdf/pricing-chart-2018-01.pdf They only give rough price ranges and production frequencies, to get real numbers one needs to request a quote. Nevertheless, they have nice price ranges relative to S-BSL7, which is the Ohara borosilicate crown glass equivalent to Schott's N-BK7. This is basically the lowest cost optical glass, so if you order a random lens or window from Edmund Scientific, it's usually made out of N-BK7 or the equivalent. Ohara says it cost ~ $10/lb in 2018.

The high-index rare earth glasses that we identified from the Nikon patent were lanthanide crowns with say index n ~ 1.7 and Abbe number ~ 50-60. From the Ohara chart color coding, these are mostly in the "medium" price range of 3.5-6 times the borosilicate crown, although there are a few that are higher. It's possible that in 1970 when these glasses were more recently developed that the difference was greater.

The small elements of a wide angle lens probably each weigh less than a ounce, although I'd guess each began as a blank that weighed maybe twice as much? So at today's prices, the bulk glass for each element in an ordinary lens might cost from $1 up to ~ $5 for a rare earth element as a very rough estimate. Certainly for mass production the price of the glass is a factor restricting the use of expensive glasses, but the fabrication and assembly costs probably count more than just the raw material cost.

Once you get to really large elements or flourides such as CaF2 or BaF2, all bets are off. There, the difficulties of casting and fabricating can be much greater and the glass really is a significant engineering problem.

Good point sir, and thanks for the link.

 

[Lachlan Young]

Yes, Olympus did its own optical design.

The rapid photographic technology advance of the the 1970's cannot be overemphasized IMO. Take any one year of the 70's and skip ahead ten years and look at a few of the many photographic jumps; Zooms, wides and ED glass tele's in 1974 and then in 1984; Match needle metering in 1976 vs Matrix metering in 1986; state of the art viewfinders and focussing screen aids of 1979 vs the AF revolution of 1989. I am sure it is possible to think of a few more (not to mention what happened with film). As the market grew with the consumer bait of "new and improved" more resources allowed each company to indulge in design and accessories, and each company could design and produce a reasonably priced 2.8 35mm optic. Maybe a couple!

There are two aspects that tend to get overlooked in the rapid changes in lens design - the arrival of on-site computer design - even Zeiss' engineers had to book time on off-site computers for lens design until the early 1970s - and the simultaneous arrival of MTF as the major design aim/ measure of lens behaviour.

 

[Christiaan Phleger]

Ha and some would say that the arrival of MTF as a 'major design aim' as the beginning of the end of lenses made with 'character'.

As for the cost analysis for the glass types the thick elemenst that I've referenced is in reality quite small; a quick measure on my copy of the 6 element 'K' optical design shows the front element having a diameter of @ 28mm.I bet the weight of those element would be in the grams.

 

[flavio81]

There are two aspects that tend to get overlooked in the rapid changes in lens design - the arrival of on-site computer design - even Zeiss' engineers had to book time on off-site computers for lens design until the early 1970s - and the simultaneous arrival of MTF as the major design aim/ measure of lens behaviour.

This is a very interesting point, because, contrary to popular belief, computers were used for optical design since the late 1950s, even in Japan. But there is a big difference between having only ONE computer available for the whole company vs more than one computer. And of course, on-site vs off-site.

Some companies even built their own computers: Fuji built the first japanese electronic computer. Canon was already a popular electronic calculator manufacturer on the '60s, so I wouldn't be suprised if they had some custom hardware at the early 60s.

 

[Christiaan Phleger]

Two quick additions; The Vivitar Series One lenses were a byproduct of using the NASA supercomputers overnight computing time to calculate their original optical designs (90mm and that macro zoom, the 28-90mm and the 28mm f/1.9 etc). I think I recall that the Vivitar project came out of Brook's Accutar re-computation of the Kodak Commercial Ektar lenses in the early 1970's.

 

[flavio81]

Two quick additions; The Vivitar Series One lenses were a byproduct of using the NASA supercomputers overnight computing time to calculate their original optical designs (90mm and that macro zoom, the 28-90mm and the 28mm f/1.9 etc).

This is not correct.

The story is well explained here:

https://blog.camera-wiki.org/2012/03/13/vivitar-historical-research-part-1/

In short: Ellis Betensky, optical designer, worked in Perkin Elmer which is a government contractor for optical systems for the NASA.

Elis Betensky approached Vivitar to design the macro focusing zoom. He used Perkin Elmer's computers for this (independent) job. And then:

“We knew Bentensky was brilliant. But we didn’t know his muscular mind was not matched by common sense, for it seemed he had completed our contract without involving the owners of his computer time. Finally he presented us with the design for the first 70-210mm Auto-Optimizing Macro-focusing Zoom Lens. And Perkin-Elmer presented us with a bill for computer time of $1M (in 1971 dollars – equivalent to $5.7M today!), and a claim of copyright infringement for using their intellectual property. Vigorous negotiations followed.”​

I've checked tests of some Series 1 lenses like the 135/2.3 or the 35-85/2.8 zoom. The offerings by Nikon or Canon are better (i.e. FD 80-200/4. FD 35-70/2.8-3.5, FD 135/3.5). Too much hype and marketing by vivitar. Yes, the 90mm macro is very good, but so are the 85 teles and 100mm macros by the original manufacturers.

 

[flavio81]

PS: This is what vivitar said on their maketing (source: printed ad for the 35-85):

So, american lens designers were doing work commissioned by the NASA (correct), and some of those same designers (well, one) "modified these lens designs" (here the marketing BS begins) ...

 

[Christiaan Phleger]

Ah that's the story! Thanks for the correction