Here are two field bird captures illustrating the capabilities of the new Canon 500 II lens and the new 2x III converter. Camera used in both was a Canon 1D Mark 4; both shots were taken wide open, aperture f/8. The Hooded Merganser shot was taken at significant distance; the crop is 55% of the full-frame image. The kingfisher shot was taken at extreme distance, requiring a very drastic crop of 22%. The 1000-pixel-wide image of the kingfisher is almost 100%; fullsize was 1087. Along with the websized image of the duck, I've included a detail at 100% from the 2700 pixel fullsize one. The fullsize version of both the duck and kingfisher images had Photoshop Smart Sharpen applied at 0.3 radius, 300 quantity, which is just about enough to offset the effect of the built-in anti-aliasing filter. The websized version of the duck was further sharpened at 0.2 radius, 300 quantity. I rarely used the old 500 with the old 2x extender; these examples show why I readily use this combination with the new equipment.