I had the Sigma 18-250mm bought as a substitute for a Tamron 18-200mm since I (was I ever goosebumps when the AF drive working) with the image quality, the processing and the noise was not satisfied. The Sigma is with me as a "holiday look on my Sony A700 and there makes good services. The image quality is not bad (I'm almost in RAW's) up to the telephoto range from 150-250mm because there subsides sharpness. Fade Out does not always help because the shutter speeds can then occur in an area where even the anti-shake of the lens has its problems. Provide better then the camera's sensitivity to 200-400 Asa, as most sensors of the cameras have no problems with low noise (down to a few antiques). It is recommended for cameras with built-anti-shake off this and the use of optics.
The lens is a nice "Always look on it" and for amateur hikers with photo addiction how to recommend me, with the image quality you can live well.
