I have 2 spotting scopes. One is a straight scope and the other is a 45* angled scope. You see vignetting in the above photo when the camera's zoom is at wide (the black space surrounding the circle) which can be lessened or removed by zooming in with the camera's lens.

Although the new Canon 7D MK2 will allow the use of a TC 2x with a 500mm f4 long telephoto, the focal reach is nowhere close to that of a spotting scope. A 7D MK2 + 500mm + 2x x 1.6x gets me about 1,600mm reach while a scope at 60x gets me 3,000mm. In the summer I had a peregrine falcon up close (can see its head up close) through the scope while a Canon long telephoto lens and tele-converters did not have the same reach.

The image above was post-processed including brightness adjustment (it was too bright but I can adjust camera settings too), sharpening and levels.