The price is enormous high for the qualilty of images. I compared this lens with my old cheap soligor 3,5-4,5/28-70. Contures of the old one are real sharp in the corners and CA's are very low, but not this lens. I regret:: this is a p o r t r a i t lens.
at such a high price I expect high sharpness still with open lens up to the corners of image; But even with f 4,5 you get not real sharp corners on 28mm; Like the concurring product of Sigma double contures in the corners and too much CA's.
nice colors,quite good sharpnes in the center; high contrast