A Canon lens for my Sony Camera

Canon 77 Close-up Lens 500D, for Lenses 70mm to 300mm, Double Element

The 500D close-up lens incorporates a double-element achromatic design for maximum optical performance. It changes the closest focusing distance from infinity to 500mm.
It has the same mount as a 77mm filter, so it can fit on the Sony 70-400, with some interesting results:

http://forums.dpreview.com/galleries/8878319148/photos/547510/ladybird