When shooting a landscape most of the time it is essential to get everything in the image from foreground to background in sharp focus. This can be difficult to accomplish. Many lenses have their sweet spot at apertures f8 or f11. However to achieve a greater depth of field a smaller aperture like f22 would be useful.
An article entitled Tack-Sharp Images by Joe Johnson, the owner of Really Right Stuff, caught my attention. He discusses the issues and procedures for achieving sharp focus throughout the image. I enjoyed his discussion and suggestions and hopefully you will find the article informative and useful as well.