The new Voigtlander Ultron 21mm f1.8 Aspherical. It is on my Bessa R4M which starts looking a bit worn - which is no wonder as it is always along. The lens is brand new - got it in Japan a couple of weeks ago and it will be on the market in the next couple of month. Really a good lens, not small - but it is a f1.8 21mm wide-angle!!!!! And at about 1/5th of it's only competition, the Summilux 21f1.4. The Ultron has less vignetting, less flare and I cant see any significant difference in sharpness either, but I will do some more testing with stuff like Technical pan later this month.
For samples check Flickr site "Voigtlander Ultron 21mm f1.8 Aspherical". I will be loading more as the days go by - including color (Ektar 100).