The wide angle is great for landscapes because it allows you to include close foreground elements. I don’t know what camera you have, but mine is a crop sensor (DX in Nikon lingo) with a 1.5X crop factor. So theoretically, the 12mm for me should be equivalent to 18mm with a full frame. @jamesstaddon and I did a little test not long ago where we set up a shot with a tripod. I took a picture with my crop sensor camera at 12mm, and then removed it from the tripod. James put his full frame camera on the tripod and took the exact same shot at 18mm. The full frame got just a slight bit more in the frame at 18mm than what I got at 12mm. Also, interestingly, the lens distortion was pretty much exactly the same between the two. So, anyhow, my point is that my recommendation of the 12-24mm zoom is based on a crop sensor. If you’re shooting with a full frame camera, you probably don’t need that wide of an angle.
