21mm (not 24 or 25)
Cheap and used (probably not Leica) since it will be for occasional landscape use only
Needs to play nicely with M9 - no red edges, no Cornerfix, etc.
Not bothered about fast aperture (for a change!)
Zeiss 21 f2.8 - Have read lots of good reports. Most expensive of the options.
CV21 f/4 - Cheapest option, but conflicting red edge reports. Solved by latest M9 firmware if manual coding selected within menu?
That's it! Any advice/recommendations appreciated.
Thank you in advance.