Designing Angénieux Optimo Ultra Compacts


Clément Mondésert (above) is the Project Manager for Angénieux Optimo Ultra Compact Zooms. He started at Thales LAS France in Saint-Héand three years ago, first as project manager for head-up displays and small zooms for helicopters and drones. Clément joined the glamour and excitement of the cine team about a year ago.

Jon Fauer: When will the Angénieux Optimo Ultra Compact 37-102 Full Frame Zoom lenses begin shipping?

Clément Mondésert: We are starting full-scale delivery of serial production Ultra Compact Zooms at the beginning of 2022 for the 37-102 mm T2.9 Full-Frame zoom. Some were already delivered at the end of December 2021. The 21-56 mm T2.9 “wide-angle” Full-Frame zoom will be delivered at the beginning of 2023. 

Why not introduce both lenses simultaneously?

For production reasons and also as a good way to get customer feedback on the first model before finishing the second one. It was the same with the Super35 Optimo zooms: the Optimo 28-76 came after the Optimo 15-40. 

When did the Optimo Ultra Compact Zoom project begin? 

The genesis of a new zoom has been a continuous process. We always scrutinize the market to understand the requirements of end-users and to consider products that might fulfill their needs. Anticipation drives our product policy. It was clear that as soon as the Full-Frame format appeared and started to expand to the point where it is now, we knew we would have to renew our entire product line in order to offer Full-Frame optimized Optimo zoom lenses. 

We started with the Optimo Ultra 12x with an IRO (Interchangeable Rear Optics) for Full-Frame as well as Super35 and Ultra35. Next, we launched Optimo Primes to cover the Full-Frame format. Then, it was time for our lightweight spherical zooms to go Full-Frame as well. 

It takes about one year from the initial concept and choosing the actual focal lengths to the optical, mechanical and electronic design. After that, we order the materials, machine the parts, polish the lenses, and then assemble everything.

Please describe the design process.

The first step was long and hard work to establish the parameters. Our optical engineers aimed at maximizing optical quality, minimizing optical defects, in a small envelope, with defined limits of size and weight. Thanks to computer simulations with our Angénieux custom-designed software, we are able to be quite accurate in predicting the optical performance of the lens.

The optical combination determines the product architecture. Then we work on the mechanics to define how we move the optical elements that must all be perfectly aligned with each other. It is also a challenging process to make everything very precise and compact.

The architecture and the detailed design of the lens take into account additional constraints: all the components must be reliable, available and industrially feasible—that is, readily manufacturable. 

As soon as we have the first product, we conduct a set of tests. Not only do we proceed with conventional optical tests, but we also subject the lens to specific environmental tests. This ensures that performance is consistent at different temperatures (the zoom is passively athermalized), when shipping, when dropped, and after an endurance test representative of the product life. Consequently, before shipping the first serial production units, we know that the lens is robust enough and meets the most demanding requirements. 

Did you say dropped?

Yes. It is part of the environmental testing program. The zoom is tested in extreme heat, humidity and cold. Then, it is placed in our typical packaging and dropped from various heights to check that the optical tuning is still the same after shipping. We want to be sure that the lens we ship from Saint-Héand, France arrives in the same condition at our customer’s destination.

Did someone go out with a prototype and shoot tests?

This time we did not made a traditional prototype. Sometimes, we might still make prototypes of sub-assemblies if we think there is a risk that we didn’t master something completely, or there are certain uncertainties, but not at the full product level. 

We unveiled the Ultra Compact in September in New York and you saw our first product. Serial production started next. In three months, we were able to go from the first product that we showed to the market to the first commercial deliveries in December. And so, the one you saw in September was not a prototype. It was our first production model. 

How did you arrive at the Full-Frame zoom focal lengths (e.g. 37-102, 21-56)? Did you multiply the Super35 values by 1.5? 

The Full-Frame Optimo 37-102 and 21-56 Ultra Compact zooms are heirs to the famous and award-winning Super35 Optimo 28-76 and 15-40. They correspond respectively to similar fields of view and 2.7x zoom ratios. In that sense, the Optimo Ultra Compact zooms are of the same lineage as the venerable Angénieux lightweight Optimo zooms: similar 2.7x zoom ratios, high-end, short, light and fast lenses.

Are these Full-Frame lenses “simply” wider diameter versions of the classic Angenieux Optimo Super35 zooms? 

Being heirs to a famous family of lenses does not mean that they are a simple reboot or copy of the former ones for a larger sensor format. For Optimo Ultra Compact, the Angénieux team completely designed new zooms from a blank page. Since we originally developed the 28-76 and 15-40 some 15 years ago, improvements have been made both in our optical calculations and design tools, as well as our industrial capabilities. We also learned a lot from our last product developments (Optimo Ultra 12x and Optimo Primes)—not only technically, but also industrially.

Making a completely new design enabled us to harvest these new means to explore new possibilities and to enhance the overall performance. So in a sense, yes, these lenses follow in the footsteps of the historical Optimo zooms that were developed 15 years ago. 

On the other hand, you cannot say that we developed the same zoom that we developed 15 years ago. In terms of industrial capabilities, we are now able to manufacture optical and mechanical components that we were not able to make before. In that sense, the Optimo Ultra Compact is completely new.

Were there any other challenges?

Specific to the Optimo Ultra Compact development is today’s environment. Due to the Covid crisis, our design engineers had to learn to work remotely. Of course, manufacturing has to be done in person. The situation is still really tough from an industrial point of view as we are facing scarcity/shortage issues in many areas, like all manufacturers. It is getting harder and harder to supply electronics, and even glass or metal. Not only do we ponder technical matters, but we also have to make decisions to ensure that we will be able to supply the material to manufacture the zooms. Supply chain is a key to success in this challenge and this is where the strengths and resources of a major group like Thales express themselves.

Is there a Super35 “speed booster” IRO for these lenses?

Our strategy as a first step is for the Optimo Ultra Compacts to be unveiled and delivered as Full-Frame-only versions. But the lens is IRO ready. It can have an interchangeable rear to adapt to other formats in the future. 

Are the Optimo Ultra Compacts made entirely in France?

Our answer is an emphatic yes. The entire design was conducted by our technical team (optical, mechanical, electronics) based in Saint-Héand, France. Industrialization and serial production is also done in our historical plant in Saint-Héand. 

Synergy and proximity between design and production are crucial to the success of such a complex new product launch. Our factory is a real asset because it gathers, in the same place, the technical design and production teams. Our production lines are also very comprehensive. We are able to machine glass for our lenses in-house. Next door, we have mechanical machining for very technical and precise inner parts, as well as outer parts of the lens. And, when you go through another door, you are in the integration line where all these components are mounted, assembled by experienced and skilled technicians, and where the zooms are tuned.

How would you compare Optimo Ultra Zooms to EZ Zooms in terms of optical design and quality?

EZ zooms are a real success because they are very lightweight, have good overall optical quality and are more affordable. However, if you put an Optimo Ultra Compact and an EZ Zoom on a lens projector, you will see the differences in terms of resolution, distortion, chromatic aberrations, etc. 

Optimo Ultra Compacts are well balanced for coverage of the entire frame: from the center to the edges. On the EZ Zooms, we made some compromises. There are far fewer compromises on the Optimos. Furthermore, Optimo Ultra Compact lenses are equipped with lens metadata and have a full-closure iris, which is not the case with EZ zooms. The image circle coverage is also wider with the Optimo Ultra Compacts. They cover Full-Frame (46.3 mm diagonal), or more, at all focal lengths and focus distances, whereas EZ Zooms exhibit a slight loss of relative illumination in some conditions.

I would say there are two main technical differences. First is the architecture. Optimos are designed with a rod-variator, a concept inherited from the classic Super35 Optimos. This way of guiding the optical elements makes the zoom very accurate and robust. It also enables our zooms to be very lightweight zooms compared to other technologies. Cams tell the optical elements where to be and the rods let them travel smoothly. We don’t have heavy, traditional ball bearings.

EZ zooms do not benefit from these technologies. And, in terms of detailed design and production, Optimos also inherit the high-end features of the family. Each product line has its reasons that are based on the type of application and production.

Do Ultra Compact Zooms match EZ Zooms in color, contrast and look?

That was not the intention. Ultra Compact Zooms match the Optimo line of Angénieux lenses: Optimo Primes and Optimo Ultra 12x. It was an important target to really have the same look for the entire high-end Optimo Full-Frame range of lenses.

How did you achieve the incredibly light weight and small size of the Full-Frame Ultra Compact Zooms?

Certainly, we use aspheric optical elements. The optical materials are a very important part of the size. And thanks to computational simulation, we are able to assess, more or less, the weight of the final products quite early in the project. That’s key to our decision-making when we begin. So, we know the weight of each optical combination even before having drawn any mechanical parts. 

Do the Ultra Compact Zooms have an internal palette option as you have with the Optimo Primes?

No. Zooms are much more complex than Primes. For example, the iris of an Optimo Ultra Compact Zoom moves in relation to an optical element in the zoom assembly as you change focal length to correct for certain parameters. An internal optical palette would not be consistent. 


The full version of this article appears in Film and Digital Times Feb 2022 Issue 113.

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