Every once in a while you come across a lens that has some very special mojo. For the photographer that is looking for that unique artistic rendering, the Leica 75mm Summilux is a lens that delivers. Based on a design by Walter Mandler (the man behind over 45 lenses, an in particular the famous Leica Noctilux), the 75 Summilux is rumoured to be his favourite design. The 75 Lux was produced for 27 years, from 1980 to 2007. Now (2013), the 75 Lux is becoming a rare and sought after lens that can be quite difficult to find.
This lens can make the ordinary, quite extraordinary. it's unique rendering with extremely shallow depth of field, coupled with a dreamy sort of sharpness, produces images that are simply like none other. This lens has been referred to as the "Extended Noctilux"; a cousin to the famous Noctilux 50mm f1.0.
The lens is intended for use on the Leica range-finder family of cameras. For shooting close subjects wide-open, focusing can be very challenging with its very shallow depth of field. Stopping it down produces images look like more like other lenses, but at f1.4, it's pure buttery bokeh magic. When you get a taste it's bokeh magic, It's really hard to imagine shooting with this lens stopped down.
The occasional listing on eBay or a careful watch of photography forums will occasionally turn one of these up for sale, but they are not easy to come by. I hunted for a while before I found mine.
Once you land one, you'll probably have it in your lens collection forever; as is the case with mine. :)