The optical quality is very low, the lens allows only little light, which is annoying because at that focal length, the slightest vibration makes a completely blurred photo. Even a good tripod is of no use here, since the lens is very light is subjected to vibration. The only solution is to mount an opening speed of at least 1 / 1000s, which is often hard given the lack of light from the lens. However, for external pictures with a beautiful sun, there is way to get satisfactory results. Here's an example of what I have had with this perspective, [...]) (ISO 2200 in full sun to go up to 1 / 2000s!). In summary, do not expect a great view, but it's very nice to play with a 500mm! In the same genre for the most demanding (eg wildlife photography or sports in outdoor), I recommend investing instead in a mirror Tamron 500mm f / 8 used, much brighter (but quite rare, about 400).
