Another test with the Canon 400mm f/2.8 IS, with double stacked TCs, 2.0x and 1.4x, for a total focal length of 1120mm (not including the 40D 1.6x crop factor). There isn't any post-processing magnification here. The size of the moon is what comes out of my camera. This is one fine photo and a great testament to the beauty of this lens. I highly recommend it.