Pursuit of perfection: Hand-crafting a Leica lens

Humans Invent interviewed Stefan Daniel to understand just how Leica lenses are made and the effort which goes into making them in Pursuit of perfection: Hand-crafting a Leica lens.

Leica’s world class lenses have become a byword for technological skill, creativity and engineering. Hand-crafted, each one is a studied riposte to the mass produced efforts made by the German company’s mainstream rivals.

With lenses comprising over 100 parts and undergoing upwards of 60 quality control checks before being allowed out into Leica stores, this is camera equipment that is both beautifully crafted and undeniably high end. Its 50mm Apo-Summicron-M Lens costs £5,400 but for those who adore the link between classic design and photographic brilliance, it’s a price worth paying. To understand just how these lenses are made and the effort which goes into making them, Humans Invent spoke to Leica’s Director of Product Management, Stefan Daniel.

How does the design process for a Leica lens begin?

We define the product concept of the lens and then we talk to our R&D people in the optical design department. They come up with a basic sketch as to what a lens could look like. That means first of all the optical design of the lens, the number of lens elements and how they are going to work together.

So, how does the R&D department take the initial design ideas and turn them into something so technically complex?

At Leica we have very experienced, very knowledgeable and very talented people in the optical design department. In fact, because it’s a very specialised discipline it takes years to get to that level of knowledge and know-how. The secret is having geniuses to make the very best lenses. Of course, that has to be followed up in the production of materials and assembly of the lenses.

You need to know, not just how to use the different lens elements, but how to use the various lens element arrays. Workers also need to be really clued up on computing systems to calculate the optimum design of the lens. It’s like composing a recipe out of different ingredients.

When it comes to the production of the lens, it’s all about taking the best materials available and machining, producing and finishing them in a very meticulous way. The lens barrel, the lens element and every part of the lens is tested during the production process, so we can avoid any faulty lens parts ending up in the complete lens system.

Leica has over 60 quality checks for its lenses during the production process. Is that a lot more than your rivals?

From what we know, we have a lot more control steps and what we can assure in the end is a very, very high, equal quality of every single copy we sell. If you don’t do that, your production quality may change and may vary a lot, depending on if somebody had a good day and made the lens in the right way. You get a better result having the proper quality control.

Why is it so important that your lenses are finished by hand? Does that really give added quality?

First of all, we do our production in batches, not in serial production. So, we do batches of 50 or 100 lenses and that requires a lot of work by hand. You cannot automate production of a single lens element, or the lacquering of the rim of a lens for only 50 lenses.

It doesn’t make any sense. So we use hand work because it’s more efficient. Also, in doing it by hand, our skilled people know exactly what they’re doing and they can assure perfect quality. Doing it by machine, you have to do control checks afterwards and maybe that’s not getting the result that everybody wants.

How long is the inspection and testing process before a Leica lens is released?

There are two major controls. One is the control of the single parts. After this step they enter the sub-assembly stage. After the sub-assembly there is a final inspection of the completely assembled lens. It depends on the lens type but a final inspection could go on for two hours.

Leica lenses can have over 100 parts. Is that particularly high? And do you tend to add more with your higher end lenses?

In high end lenses or zoom lenses, that number can go up to 200 or 250 parts. For a Leica S lens, which also includes automatic focus and automatic aperture, it can be that high too. It’s not our goal to put as many parts in the lens as possible. Quite the opposite. We try to reduce parts because it adds cost and complexity. Sometimes it’s necessary to have that to fill the product specification. Of course, we are limited by the number of lenses we can produce. First of all, as there aren’t many people who have the skills to do it and also by the availability of parts. Some glass types are only melted for Leica cameras and our suppliers do that once or twice a year only. If we don’t order enough material then the quantity of lenses we can make is limited.