These images were taken with the 1DX/400mm f/2.8 IS II coupled with the 1.4X III or the 2.0X III tele-extenders at maximum aperture: 560mm at f/4 or 800mm at f/5.6.

The birds were approximately ten feet away from the camera. The images were cropped and re-sized but a few full res crops are included. Note that the depth of field of the setup with the 1.4X is only about 6mm; with the 2.0X it is only a thin 3.6mm. This extremely small species of birds is a real test of feather detail reproduction.