The current SUMMICRON has an interesting optics: it has two concave elements on both sides of the Gauss optics. Its roots originally go back to the first generation pre-aspherical SUMMILUX 35mm and indeed they are very similar to each other. I guess the reason they applied the aspherical design is to improve the picture quality in the corners rather than to eliminate spherical aberrations　because the caliber is f2. This approach was inherited to the latter versions, and it is this current version that influenced other modern Leica lenses. In that sense, this SUMMICRON is a milestone of the current Leica lens line-up, and in fact their performance is on a different level since this lens was released. It’s razor-sharp wide open and cuts like a knife, but at the same time, it has rich tonality and the drawing is round. It’s also solid because of the smooth bokeh increasing to the background. If you use a 35mm as a normal lens, just go for this one.