I'm looking for a lens or fixed-lens rangefinder that has the same kind of light and focus falloff you would see on a lomo or a Noctilux, but that is focuseable and that doesn't cost $3000. I was initially thinking of a Sonnar-type lens like a pre-war Sonnar Opton 50 1.5, as these seem to be relatively cheap and available, or a Jupiter-3 50 1.5, which is coated. How are these lenses wide-open, and how much does coated/uncoated affect contrast on a Sonnar lens? I was also thinking Sonnar because of the supposedly nice bokeh. What else might good be a candidate for bad falloff?