Adam, I love the 50 Nocti for street shots, as you have such a variety of renderings you can choose from at different f stops. The renderings change very quickly from 1.0 to 1.2, and again to 1.4. Light 3 different lenses. The issue with the 50 Nocti f/1.0 last version, not having the aspherical elements, is the focus shift, and being very mindful of it. In my case at MFD, at f/1.0, 1.2, 1.4 and f1.8 the focus is spot on. After f/1.8 to 2.0 there is some back focus at MFD, but at 1.5m this is fine. At f/2.8 to 4.0 there is back focus at MFD, but again at 1.5 to 2.0m this is within the DOF. This is great for the full portrait street shots. Then by f/5.6 the MFD and further the focus is spot on again. Of course, the lens does need to be closely matched to your M9 to make sure this does not drive you crazy!
With the 50 Lux, it is an amazing lens too, light, ergonomic and accurate focusing you cannot go past it, as it just works brilliantly!
Edwin, the 50 Lux is a better choice 90% of the time
