I currently own a Canon 7D and want to buy a Canon L series zoom lens. I am not worried about weight just what is the best option. I would like to use it for wildlife but also any other outdoor photography including sports and motor sports. I have considered three lenses within my budget. A Canon 75-300mm, the lightweight Canon 70-200mm and up to the Canon 100-400mm. My current lens is an L series 28-105mm that takes a 77mm filter. With the exception of the Canon 100-400mm lenses the other two are 68mm size lenses. Does the width of the lens make that much of a difference to consider going for the 100-400mm size lens for more quality photographs? Greg