1 aspherical, 1 super extra low dispersion, 1 extra low dispersion
It is an impressive lens in many ways. It comes packed with a ton of features, but also in a huge and heavy housing. Given the size, the weight and last but not least the price, the build quality is a bit disappointing, because of the amount of plastic parts, even though everything is tightly assembled. Optically, the lens delivers very good results. [...] In terms of image resolution, there is nothing to complain about.