Pentacon Six mount fits Kiev 88СМ Zeiss Aus Jena S 180mm F:2.8 lens for Pentacon 6 & Kiev 88 cameras. http://www.pentaconsix.com/150_180mm.htm
According to the website about the Pentacon Six system..."A very short step takes us to the
180mm Carl Zeiss Jena Sonnar. This lens is MUCH sharper than the 150mm Arsenal Kaleinar. Both are f/2.8 lenses, and the Kaleinar is VERY soft at maximum aperture, whereas the Sonnar is still very sharp. In fact, the Sonnar’s results at f/2.8 are really quite outstanding, and while there is a slight increase in contrast at f/11, when you start off this good, there is little more that is gainable when stopping down, other than the obvious increase in depth of field. Although not required for this test shot, the 180mm Sonnar also focusses a LOT closer than the 150mm Kaleinar, making it ideal for head-and-shoulders portraits, whereas the Kaleinar can’t get quite close enough, unless a short extension tube is used. With a lens as sharp as the Sonnar, a soft-focus filter could be useful for at least female portraits."