Hi Guys

I took the canon 100-400mm L series 4.5-5.6 zoom down to the beach today to do some long focal length tests. The lens had a 1.4x extender on it as well.

http://vimeo.com/41046979

Here's the video with some shots from the day, you can clearly see the difference in visual quality, most shots at the 100mm end of the lens look quite nice and sharp. but shots like the one starting at 0:38 seconds and at 1:58 were taken at the 500mm end and the deterioration of detail and edge sharpness and contrast becomes quite apparent.