The 12-35 mm for landscape.

I bought my 12-35mm because of the weather sealing and little else -- other than I'd heard it was extremely well built.  I had no expectations about its IQ being significantly better than the 14-45 I have (and love) and was actually fully resigned to the possibility that it would actually be worse.

I do LOVE extremely wide angle lenses, like my 7-14mm, primarily for interior shots and closeups of faces, things, etc.  (i.e. I don't do a lot of landscapes, kind of don't get the point of a wide-angle lens for landscapes since to get the real wide stuff you need to have an image where everything of interest is impossibly far on the horizon -- why not just do a panning shot and stitch them together?  But I digress).

Because of this, the fact that the 12-35 went down to 12mm was a little exciting.  Suffice to say that after owning this lens for month, I can say:

1.  The IQ is significantly better than I was led to believe -- I am very pleasantly surprised.  It appears to be on a par not only with the 14-45mm, but also (at 25mm) in the ballpark of my 25mm PanLeica.

2.  It's not at all bad wide-open and, at least from 12-14mm, is giving the 7-14mm a bit of a run, particularly since the latter is significantly slower than the f2.8 12-34.

Took these today out back on my farm.  Nothing to write home about, but should give you some idea.  They are landscapes and that's not my forte' and I was just playing around...

RAW image from GH3 processed into JPEG by Aperture.  Note CA.

In-camera HDR of same scene above