The Canon 40mm just came out earlier this year in 2012. It has some pretty high reviews at a pretty great price! Currently the 40mm you can get at Amazon for $199.99 which really isn’t that bad in my opinion for a lens. I still can’t get over how slick and thin this lens is. Do you thing the 400mm will ever look anything like this, hehe probably not!
Official Product Description:
Ultra-slim and lightweight design
Aspherical lens element delivers high image quality from the center to the periphery
Advanced optical design enables a bright f/2.8, compact optical system at 40mm
Optimized lens coatings ensure exceptional color balance while minimizing ghosting and flare
Built-in stepping motor provides smooth and quiet autofocus when shooting video with Canon EOS Rebel T4i DSLR