Just got this today. I\'m not a long lens guy, but I wanted one cheap to play with and I thought it could be useful for my occasional zoo visit. It turns out that I probably won\'t be bringing it to zoo, 800 mm is just too much for me to handle, and my tripod probably doesn\'t cut it.
Haven\'t played much with it, but the lens has a very low contrast, the nature of the beast I guess. It is also very soft. But After a pretty extreme contrast boost and mild sharpening, I guess it\'s acceptable for A4 sized print. This is shot outside my window on 5D MkII:
100% crop
The shot obviously wasn\'t done with the most rigorous testing methodology, but IMO it is pretty representative of the lens\' performance.