I had an old Sigma from my analog A1-time, unfortunately this was not on my new EOS 400D can be used. SIGMA was very helpful - they offered me to demand to take back my old lens. For me I could choose a new, compatible part for a very concessionary price. For this procedure first praise to SIGMA!
Spontaneously I decided for the 18-200 without having it previously tested times somewhere. That was my fault! I would have namely found that the lens in the upper zoom range is not just really sharp. In addition, I became painfully aware that the light intensity at 200mm (6.3) extremely goes down to the basement. In the lower focal length ranges I am highly satisfied with the images, however.
Now how do I get to 4 points? The lens is well made, it rattles nothing, the picture quality is 18 - (approx) 100mm really very good, the support provided by the SIGMA-sales service is also good.
The deduction of points is reached, because the lens at 200mm is good practice for snapshots only. But I admit that I previously could have recognized this shortcoming with a little thought. I now try loszubekommen this lens again and bring me instead one or two lenses with a smaller focal length range and for higher light intensity.