Joy without click
Uwe Weber, head of construction at ZEISS and winner of the ‘technology Oscar’ , has launched many lenses during his career. His latest coup: the de-click function of the Milvus lenses.
Some ideas that initially seem brilliant end up facing many setbacks. Other ideas are so easy to implement, you wonder why no one else came up with the idea. The de-click function of the Milvus lenses belongs to the second category. “It took a half a day to draw it and after four weeks, the function was ready for production,” says Uwe Weber. Photographers and cinematographers are enthusiastic about it and their feedback has been consistently positive.
The decision to develop an aperture ring with a mechanical catch that can be turned on and off arose following conversations with professional photographers and filmmakers. Increasingly, professionals use their digital cameras and camera lenses to film in almost motion-picture quality thanks to HD, sometimes up to a 4k resolution. But what photographers love – namely that palpable click of the aperture ring in order to control the depth of field – turns out to be bothersome when shooting a video, because a camera person would normally want the ability to smoothly expand, or diminish, the depth of field range. Experienced do-it-yourselfers would tinker with the lens until they found a solution: opening the lenses and removing the click mechanism. If the user wanted to use the click function again, the complex procedure had to be reversed. And of course, the whole procedure would mean losing the guarantee on the lens.
In order to spare ZEISS clients this operation on the open lens, Weber’s team developed the de-click function as a purely mechanical solution. With the half turn of a small slotted screw on the mount surface of the lens, the function can be turned on or off. The mechanics hold back a small spring, which presses a ball against the aperture ring when in the photo modus. Without the spring, the ball falls back and is held by grease; the aperture ring can now turn without the photographer feeling the catch. It sounds simple enough – and yet the feature is so unique and sophisticated that Uwe Weber has a patent on it – one of many patents he has collected over his 25-year career with ZEISS. This type of de-click function is as yet available with the ZEISS Milvus ZF.2 lenses. The ZEISS Loxia lenses also have a de-click function; however, due to the construction of the lens, it differs from a technical standpoint.
Users regularly ask why the ZE lenses don’t have an aperture ring that would theoretically allow them to have a smoothly variable aperture through a de-click function, as is found on the ZF.2 lenses. The answer is that it’s technically difficult to combine an aperture that is electronically controlled, like the ZE lenses, with a mechanical aperture ring. This is mainly due to the camera system for which the ZE lenses were developed. Earlier camera models were not designed to include an aperture that was manually pre-selected on the aperture ring of an attached lens in the exposure control. The details and reasons for this can be best answered by the respective camera maker.
Like all third-party manufacturers of lenses, ZEISS attaches great importance to making its lenses completely compatible with all cameras. That’s why ZEISS lenses for each system have the same functional scope as the original lenses that come with a camera. Only the ZF.2, ZEISS Loxia and ZEISS Touit lenses with X mount are available with an aperture ring on the lens, as the respective camera maker has made this technically possible for these systems.
Developing the new feature did not always go smoothly. “Sometimes you have what seems to be a really simple idea, but in the course of the development it becomes more and more complex,” notes Weber. “I compare it to going up a mountain and then down. Once you’ve achieved that and found a solution, you wonder why you couldn’t have found a tunnel in the mountain, which would have taken you to that solution faster.”
Weber, 51 years old, discovered a passion for photography early in his life. He bought a reflex camera when he was 15 with money earned from his first vacation job. Today he occasionally takes pictures of weddings, but he never wanted to pursue a career as a professional photographer. “I am more interested in the technology.” After completing his university studies in precision engineering, Weber joined the mechanical design department of ZEISS in 1990. Ten years later, he became head of that department. Since 2000, many lens prototypes have travelled through his hands, including numerous legendary models for Contax, Hasselblad and of course ARRI, the company that has won many ‘technology Oscars’ in Hollywood for its products for the Hollywood film industry. In 2012, it was Weber’s turn to win an Oscar: he received the coveted Scientific and Engineering Award®, – the so-called ‘technology Oscar’ – on February 11, 2012, Los Angeles for the mechanical design of the legendary ARRI/ZEISS Master Prime lenses.
The design of lenses has changed dramatically since the early 1990s. Today, many steps in the design process have become more systematic and much faster. Computers and software support the work and make some things easier. Depictive simulations can find bothersome reflections, and the finite-element analysis calculates the stability of the barrel. And the mechanical features – high robustness and a pleasant feel – are important characteristics which distinguish ZEISS products from competitor products.
The future remains exciting
Is progress still possible with lenses? And if not: will employees in Weber’s team one day be without a job? “As technical designers of lenses, there’s also the fear that there will be saturation at some point. But the last few years have shown that lens development has never stood still. There are always new ideas, such as the triumph of digital photography, the high dynamic range (HDR) and the trend toward higher and higher resolution, such as 4K or even 8K with movies. “In order to keep pace with such developments, improving details is not enough. As always, we still need to make large jumps in innovation, for example to reduce stray light and reflections.”
Such leaps are still possible. Several years ago, for example, ZEISS created a brand-new market with its Compact Prime CP.2 lenses – a market that ZEISS’s competitors have now also noticed. And in the field of camera lenses, there are surprises, such as the OLED display with the new Batis lenses, which shows the depth of field range, even when it’s completely dark. A mechanical solution was quickly thrown out, recalls Weber, and ultimately, it was decided to take an innovative route. “We always keep an eye out for interesting technologies outside our market and use them, when possible, for our own purposes.”
Weber won’t reveal what his team is working on right now. But he says it’s going to be another exciting product. And even after that product launch, more work lies ahead. “I have enough ideas to easily last until my retirement.“