I have both and they are very different. Everyone has his/her own take on landscapes, but my feeling is that if you like prominent features in the foreground go for the 40mm, otherwise the 50mm. But then again, I happen to think that the 50mm could almost be used as one's standard lens (in my 35mm film days, my standard was a 28mm). If you can afford it, get both - if not, get the 40mm first - it's just such fun. If you are worried by distortion in landscape photography the 40mm should be just your sort of lens.