We are trying to find out why the known EF 200-400mm f/4L IS 1.4x lens has delayed again and again. Now Canon Rumors give us the reason: It need redesigned.
From CR: The latest we’ve heard, and from a pretty knowledgeable person is that the lens has needed a redesign in regards to the “bump” that holds the built-in 1.4 TC. The person wouldn’t elaborate as to why it was an issue, but it was brought to the attention of Canon at the Olympics that some pros were complaining that the “bump”, or a function of the “bump” got in the way of something. Again, what the something was wasn’t elaborated upon. This is about the only explanation beyond “manufacturing issues”, which could also be playing a small roll. However, lately we’ve seen that the new super-telephoto lenses are now making their way to “in stock” status around the planet. Maybe we’re closer to the new supertelephoto finally being announced.