Lens metadata is increasingly playing an important role in productions. From helping focus pullers and DITs to informing real-time virtual productions like The Mandalorian, understanding how useful it can be is a must for any cinematographer or filmmaker. 

If you ever picked up a Sony FE or Canon EF lens, you've probably noticed those little metal contact points on the mount. Those are electronic communication points that allow the lens to talk to the camera so features like autofocus function correctly. Other lenses allow metadata to pass through, providing information for focal length, iris, and focus settings.

With that info, it allows teams to place virtual objects into scenes for preview or for talent interaction. 

Metadata is also used by visual effects teams to build realistic elements that match seamlessly with what was shot practically. Instead of manually tracking or tracing the camera movement, the metadata allows them to skip that step in a way by offering a starting point for that scene. There are also some other cool things metadata can do like automatically calibrate your lens to save you time on set.

Similar to lens mounts, there isn't a standard across the industry. Currently, there are three main players. There's Cooke i/Technology, ZEISS eXtended Data, and ARRI LDS (Lens Data System). 

The metadata of all three are nearly identical, but there are some differences. Each can send focus, iris, and zoom settings, but i/Technology and ZEISS eXtended Data can only pass that information out, where LDS can be fully integrated into ARRI's lenses, cameras, and accessories. This way an ARRI lens can talk to an ARRI camera, or vice versa. 

The catch with LDS is that it's generally only a part of ARRI camera systems because of a steeper licensing fee, while i/Technology is essentially open-source. Because of that, i/Technology has been widely adopted by lens and camera manufacturers, including ARRI. 

But ZEISS eXtended Data might have an advantage over both. Not only does it pass through the same metadata, but it includes frame-by-frame information on lens distortion and shading characteristics. This can be helpful with virtual production and visual effects because the elements of distortion can be adjusted or replaced to create a more realistic-looking scene. 

To get you up to speed about all three, the team over at Chrosziel is having a seminar where they will do a live readout of lens metadata for ARRI LDS, Cooke i/Technology, and ZEISS eXtended Data on Feb. 22, 2021, at 1 p.m. ET/10 a.m. PT. 

You can register for the free seminar here.

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Cinematography & Cameras