Another sample from the archives using the Kenko Tele converter on the Canon EF 70-300. A little polishing in PS can get really acceptable results.. at least it seems when compared to the original ;)
Camera Canon EOS Digital Rebel XSi
Exposure 0.003 sec (1/320)
Aperture f/7.1
Focal Length 300 mm
ISO Speed 400
Exposure Bias 0 EV
Lens EF 70-300
Teleconverter Kenko Pro DG 300 1.4x