In the Canon EF 25-105mm f/4 L USM IS lens specs, it says that the lens coating is "Super Spectra Coating". What is the Super Spectra Coating and how it differs from other types of coating?
Super spectra is the same as "Double whammy super bling extended +++ coating" - ie it is a marketing name that by itself may or may not have some meaning. Canon say: "Canon's multi layer Super Spectra coating allows up to 99.9% of light through to the CMOS sensor, over a range that extends from ultra violet to near-infrared light. As well as minimising ghosting and flare, Super Spectra Coating ensures a consistent colour balance across all EF lenses and plays a key part in delivering the sharp, high-contrast results that Canon lenses are renowned for."– Russell McMahonJun 4, 2012 at 2:53
4ie it means "We use a coating that we have developed that does what we need a coating to do. It works better than the old stuff we used to use. Don't ask."– Russell McMahonJun 4, 2012 at 2:55
Super Spectra Coating is Canon's form of "multi-layered anti-reflective lens coating". Every brand usually names their key features, processes, and functions...such as lens coatings. Super Spectra is Canon's...and these days, its actually the legacy form of lens coating. On all new lenses released within the last few years, Canon uses SWC, or SubWavelength Coating...a form of nanotech coating that is far superior to any other prior form of anti-reflective coating used by any manufacturer (except Nikon, who uses something similar they have dubbed Nano Crystal Coat.)
All anti-reflective coatings are technically sub-wavelength in thickness. That's why they work. As such, the whole thing is basically devoid of any real meaning. Jun 4, 2012 at 8:19
@FakeName: True, however multicoating works because each coating is a very specific thickness that is capable of canceling out reflected light. SWC is entirely different and functions in a completely different way...the aim is to avoid reflection entirely, and guide as much light through the coating layer into the lens as possible. SWC coating is much thinner than layered coatings, and is not really layered at all. See my answer on Nanocoating for more details about the differences between multicoating and nanocoating.– jristaJun 4, 2012 at 17:13