[davidmanze]

All three lenses are Sigma Art types. And less or more elements - it also counts how large these are, I think.

135 Specs

105 specs

85 specs

The Otus has 14/11 lenses/groups

    Much as I had my doubts about the AF accuracy of the earlier Art lenses .... the images that come out of them is inarguable .....
 .... the more recent art glass seems to have refined the AF performance to OEM levels of accuracy and most of the problems have disappeared ..... along with the complaints in the forums.

   I have no desperate use for it ....... but the 105mm F1.4 portrait lens looks like a dream optic ...... and considerably more affordable than the Nikkor version.