I recently purchased a used Tamron 18-200 aspherical LD XR DiII used from amazon(for credibility's sake). I have no wide angle on my Canon 5D so i figured this will serve till i have enough money for Canon wides...
The problem now is that the lens vignettes at every focal length. Thinking i'm too smart for that, i removed the lens hood. Guess what? No difference. the vignetting around 18-35 is not a vignette, its a photo circle with the image appearing circular, shrouded by huge vignettes....only 200 gives a lens hood type of vignette (without the lens hood on). My frustration is increasing...please what could be the problem?