I use the Voigtlander 21/4 lens with the dedicated finder and I'm perfectly happy with the quality of the finder. The only thing that worries me is the fact that the foot is plastic. I have read really good reviews of the Russian 20mm finder and it's about as economical as you can expect. It's available here: http://www.dvdtechcameras.com/lens/leica/2/2.htm