FEATURE | SMART LENSES
Zooms are complex, which makes them great candidates for metadata
because lenses are darker in the corners than they are in the centre. Then with these factors unravelled, you put your CG character in and the character sticks to the table. Then you can re-ravel, if I can invent a word, so it looks photographically natural and the character stays stuck to the table.” Clearly, Zellan’s ideal of a single system for lens metadata hasn’t quite panned out. LDS and /i are the principal two, with LDS 2 in progress, a proprietary system from Canon, and Zeiss using /i to deliver the distortion data Stump discusses. Snehal Patel, from Zeiss, is quick to credit Cooke’s work. “Les has specified new fields that are very interesting to VFX: shading and distortion profiles. There are some fields that are absolutely required, the serial number of the lens, focus and iris marks, the focal length of the lens and the serial number and name.” Other data is optional, but powerful. DISTORTION MAPPING Zeiss’s distortion mapping, for instance, is integrated with the variable sensor area features of Red’s cameras, so that changing shooting format does not require recalibration. “You can now change your frame,” Patel says. “You can go from 7.5k to 7k and you don’t have to shoot all new charts. It’s completely automated. We did a lot on the back end with the plug-ins – we have plug-ins for Nuke, After Effects and Resolve.”
Metadata has been available from Fujifilm lenses since the Cabrio range, with removable electronic modules, as company spokesperson Marc Horner explains: “The metadata was much simpler in that it was – where’s the iris, where’s the focus, where’s the zoom? I know that it supported the Arri LDS and the /i, and it does to this day. The difference with the Premista zooms is that all that encoding is done inside. They don’t need an additional device attached to the side.” Zooms are complex, which makes them great candidates for metadata, and Fujifilm uses Zeiss’s technology to handle distortion data. Horner explains: “Each lens will have been mapped, put in front of a grid at the factory and at every single focal length and
focus position, the lens distortion will have been recorded and stored. That’s a process that every VFX house could do themselves and I understand that it’s a process that takes half a day. A zoom can take a lot longer. I was talking to Ncam about a show that had 17 VFX vendors. They had to map the entire set of lenses and then pretty much every one of those VFX houses also had to map the whole set. Think of the cost of having those lenses on rental for shooting – and you need them on rental for another month, to ship them around the world. That can be fixed.” VFX EXTRACTION Getting the data to post-production also means getting it through all the processes
54 DEF I N I T ION | OCTOBER 20 1 9
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