Sigma 18-200mm F3.5-6.3 DC Macro OS HSM C Canon mount lens review: Worthy upgrade?By Kevin Carter - Friday March 28 2014 Lens Review
Sigma 18-200mm F3.5-6.3 DC Macro OS HSM C Canon vs Sigma 18-200mm F3.5-6.3 DC Macro OS HSM Canon
With similar DxOMark scores compared to its predecessor the new model appears to be only a minor improvement.
But if we look more closely the significant advances have been made with regard to sharpness at the longer of the zoom range. Even when stopped down the older model was quite soft, even the center. At 18mm though the new model has some slight field curvature with an area of softness surrounding the center. The older model has better uniformity at the wider end, but not the same level of sharpness.
Transmission, distortion and vignetting are remarkably similar though the newer, revised optical formula has also reduced lateral chromatic aberration noticeable at either end on the older model.