Blue Goo gets Bluer

Dec 22, 2020 | Canon, Lenses, News, Patents

Canon is goosing its existing “Blue Goo” technology (essentially a materials advance that first came out with the revered EF 35mm f/1.4 L II) to be even more corrective with an even higher transmittance. The tech – used in only a few lenses to date that we know of – can almost perfectly correct color aberrations. At the time of the launch Canon’s marketing team termed it “blue refractive optics,” probably to avoid calling it what it really is: a plastic resin. Further obscuring language Canon put in its marketing materials used the term “organic compound,” another fancy word for many plastics. In response, forum dwellers quickly adopted the semi-mocking term “blue goo.” They mocked the marketing team, but no one – at least no one who shot the 35 L II – mocked the technology itself.

In their quietly geeky way, Canon has been experimenting with additional changes to the resins, doping it with different things and narrowing down which parts of the molecules appear to be controlling the effect on both refraction indices and transmittance. Out of this now comes a new patent with a resin doped just so. The graph below shows secondary dispersion on the x axis on various attempted formulae, with the resin options clearly showing the most extreme performance over on the right.

It made sense to launch the Blue Goo technology with a super expensive prime that was destined to become a Canon classic lens, as it helped to inoculate accusations of cheaping out with the use of plastic element. That said, the patent application above speaks in its claims section about the superiority of plastics, in part due to the ease of forming the lens element shapes, but also because it reduces expense. It may even be that the older Blue Goo technology has been quietly used in cheap lenses in the last few years to provide better bang for buck.

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