« on: November 18, 2013, 06:25:21 PM »
Get a tripod and practice taking multiple shots with the camera in portrait orientation using your existing 100mm lens. I would also recommend a circular polarizer. Overlap the stiched images by 25-30%. If you have the time to set-up and use good technique, you should get outstanding landscapes. Make sure you shoot manually and have a level tripod. If you already have a tripod and a polarizer, you have spent nothing.
If you really want another lens, I would consider the original 24-70 f2.8 L. It can be purchased for ~$1000.00. Stop it down to around 5.6 and it will be plenty sharp. However, it will not be as sharp as a vertically stitched 100mm. Just quicker and easier to get the shot.