It is designed in Solms and built in Japan, has 8 lenses, of which one surface is aspherical. With this lens Leica introduces a fourth strategy and that is building a low aperture lens to very high optical standards of performance. It has been a truism to assume that wider aperture lenses, because of a more sophisticated design would be capable of better imagery than smaller aperture lenses of the same focal length. Again this is not true anymore as a universal rule. It is not well recognized how difficult it is for a designer to control aberrations when stepping up one stop.
Many aberrations grow in magnitude with a cube power when the aperture is doubled.
And that is quite hefty. A third truism is the notion that a lens can be designed for contrast or resolution. Again this notion has had in the past a very limited validity and is now obsolete. In the recent past a well designed wide aperture lens could hold its own against smaller aperture versions, because these versions most often belonged to the first type of strategy outlined above. In the M line the Tri-Elmar makes the same point.