I got a little time with the Voightlander 20mm pancake and some people here wanted to know about the lens, here are my notes.
First off, the lens you can buy now is discontinued, including the one on the B&H website. I mentioned this to them but they didn't have much of a response to that. Anyhow, an updated one is coming out in August which has a metal knurling focus ring instead of a rubber covered ring. I think this is a great idea, I like all metal, especially in a lens like this.
The lens is solid and small. Not as solid as I was expecting, but I'm not sure how it could be made more 'reassuring'. Getting rid of the rubber as I mentioned, and there is some plastic in there.
Anyhow, on the IQ. I didn't do extensive testing just some shooting around the house. What I found is that the lens won't give you the best results without coaxing. Canon lenses seem to just deliver to the best that is possible given the situation. This camera tends to give you worse results, and you have to push it to give better.
It does vignette and is soft wide open in the corners with a FF. This is part of what I mean by the lens making you work - it wants to take certain types of pictures and not others. I took a night shot with a focused flash and it looked great. I also took a general wide angle daytime outside snapshot and it didn't look so good. The lens likes more considered 'art shots' and performs better in those.
For some reason I found myself tilting the camera and doing more creative framing than with the big lenses. I never
do that with my other lenses. I think the big zooms encourage you to think 'do it professionally', and this little lens encourages you to 'think creatively' more.
The lack of autofocus was a no brainer. You get a focus light in the viewfinder when it finds focus, or you can get a Eg-s manual focus screen. My first camera was an AE-1, maybe somebody who hasn't used a manual focus lens would feel differently but I actually preferred it. Nothing worse than having a 'hunting focus' lens when you're trying to take a shot.
Finally, the lens has a characteristic that I noticed in Flickr shots and in my own. Hard to describe ... kind of like if you were taking pictures with film, and the film had some slight harsh, jagged contrasty look. Flat colors, not three dimensional. By contrast the 70-200 2.8 II has dreamy 'true to life' colors and depth, this one creates a stark look. I like the look, my wife loved it. More old school than new school, shots look like they might be from the 70's or something, and I think it's a combination of the old school optics and digital resolution. This is a characteristic that makes the camera want to take 'art' shots, and not snapshots.
Neat lens, my ideal focal length, I'll probably buy the new version when it comes out in August. There is a Flickr group dedicated to the lens if you're interested. Here is a picture from that group that captures the lens for me