Excellent for those who know what it is and how to use it.
26 February 2013
Summary: Please note that the items here have not been specified whether they are the version I or II of the lens. The newer version offers more axes and degrees of movement. Image quality is better. The filter thread in the version II is 82 mm, that is how you can tell which version you are looking at.
Summary: Canon really earned their money with this lens! It is difficult and expensive to manufacture, and has a large aspherical lens as the front element for performance approaching apochromats. Version II of this lens has just been released, but it sells for twice the price.
This quality, yet heavy lens allows you to really change your perspective!
17 September 2012
Summary: In architectural photography- this lens compensates for the appearance that upright lines, such as the sides of buildings, windows, etc- are leaning away from you as they climb above eye-level.