What's with Canon's white lens?

Canon white lenses are mostly L (professional) telescopic zoom lenses, which are generally used for sports photography and animal photography. That is, people often say "long guns and short guns" series. Most lenses adopt large aperture design (constant aperture). The white design can reduce the heat absorbed by the lens barrel, which is equivalent to protecting fluorite lenses.

In order to ensure excellent performance in various environments, its appearance is more solid. This kind of lens generally adopts fluorite lens and multilayer coated ultra-low dispersion lens, with fine workmanship, excellent quality and higher price than other lenses.

The material and technology of this kind of lens are different from those of black lens, because its aperture is very large, which can ensure sufficient luminous flux.

Extended data:

Red circle: professional Quan Huafu lens, good workmanship, dustproof and waterproof, good imaging quality (not necessarily), and relatively large maximum aperture. The maximum aperture of various zoom lenses is constant, and many ultra-low dispersion lenses, aspherical lenses and even fluorite lenses are usually used.

Green circle: professional Quan Huafu lens with diffractive optical element (DO element). At present, there are only 70 ~ 300mm F4.5-5.6Dois and 400mmF4DOIS. I wonder if this technology is good.

Yellow (gold ring): Ordinary Quan Huafu lenses are generally not dustproof and waterproof, and the imaging is not necessarily bad. The maximum aperture is small, and the zoom head has no constant maximum aperture. It is impossible to use many aspherical mirrors and low dispersion lenses, let alone fluorite.