A Step Closer to Lens Metadata Standardization

By Les Zellan, Chairman and Owner, Cooke Optics

At NAB this year, a milestone in lens technology was reached when, together with our friends at Panavision, RED Digital Cinema, Canon, Blackmagic Design, CW Sonderoptic and Sony, Cooke Optics announced the industry-defining project to standardize the collection of lens metadata from PL and selected Panavision mount lenses on the /i Technology protocol.

The value of metadata is now completely accepted for archiving and in many areas of production, particularly news, where it is crucial for enabling people to search, find and manage content quickly and easily. However, it is still largely overlooked at the acquisition stage. Although some metadata from the lens is being used on set for monitoring levels, there is so much more it could do that could save significant time and money during production and post production.

At Cooke Optics – which has over 130 years of experience in lens development and a Scientific and Technical Academy Award® among many other industry accolades – we recognized this deficit in lens metadata capture around 18 years ago, and set out to create a metadata protocol that would provide the industry with a digital open standard to gather and share lens data, ensuring compatibility from acquisition to post-production. The result was /i (Intelligent) Technology.

The /i project was started with just the idea of delivering basic information (as a continuous remote readout), such as iris; focus; depth of field; hyperfocal distance; and circles of confusion (which is related to the film or camera sensor format – and can be user selectable or potentially could be set by the camera). The information can be digitally recorded for every frame and stored as metadata, accessible via cable connector near the lens mount and/or contacts in the PL mount that sync with /i compatible cameras and other equipment.

As lens manufacturers, all of this had to be carried out in the lens. We couldn’t farm it out to the camera because we didn’t make them. The lens contains various encoders and sensors, as well as the computational power to calculate what is happening and deliver meaningful results.

With persistence and determination (and a very reasonable £1 licence fee) we’ve been promoting /i across the production technology industry, and today there are over 30 /i Technology partners – including many of the industry’s leading camera, lens, monitoring, data recording and post-production manufacturers, which support /i Technology in their products. The open nature of the protocol means that manufacturers can integrate it to work with their technology, and not the other way around – so we have a standard way to collect this data, while manufacturers can still maintain the unique nature and design of their lenses or cameras.

Digital cameras that are /i compatible can talk to /i lenses directly via four contacts in the lens mount as well as an external communication connector. The /i Technology provides the framework; the extent of camera data made available is the choice of each camera manufacturer via its software and hardware.

By feeding this lens data to post-production teams, they can not only save time and cost but also ensure a better quality product because the digital data provided takes the guess work out of many processes – the VFX artists can, therefore,create effects and 3D models that are more accurate, with much greater speed.

Importantly, capturing lens metadata does not affect normal operations on set at all. Metadata recording takes place without having to monitor or manipulate anything. Data records to the digital or film recording medium, or to an SD card; there are no specialists required on set and the DP needn’t worry about fussing with complicated accessories.

Since the announcement at NAB, three more /i partners have signalled their support to standardize the protocol. Zeiss is already delivering its version of /i, known as XD, in its new CP.3 lenses, and Ambient and Pomfort have recently signed up, providing new avenues to move data from the set to post-production.

Cooke’s goal has always been to give /i to the wider industry, in order to provide film-makers and post-production teams around the world the crucial lens data they need, in a format that is universally recognized. The collaboration announced at NAB 2017 takes us a big step closer to achieving that goal, as we continue to pick up momentum for a common language (not common hardware) for metadata communications on set and in post.


Les Zellan graduated from Carnegie-Mellon University with a master’s degree in Technical Theatre. He designed theatrical stage lighting systems before becoming sales director for FERCO, a film equipment rental company in New York City. He formed Zellan Enterprises in 1979 to promote and sell film equipment.

In 1998, Zellan purchased the Cooke lens division from Taylor-Hobson. Under his ownership Cooke Optics has won many awards including the Academy Award® of Merit, CINEC awards and a Primetime Emmy.

Zellan is an associate member of the American Society of Cinematographers, a member of the Motion Picture Academy, and lectures on the art of lens manufacture.

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