Sigma 18-200mm f/3.5-6.3 for Canon

As a professional photographer for over 40 years, I came into the digital age kicking and screaming all the way. I now use a Canon 20D for most of my documentation photos. I have used the 18-125 extensively since it first came out and decided to get the 18-200 as a back-up. I like the idea of a little more oomph at the telephoto end. I have been impressed with both, the shots are sharp, clear, with good contrast, the close focus is impressive and the fact that you don't have to change lenses (which introduces dust to the sensor)as often makes it ideal as the main lens for your camera. I only wish it had a faster aperture. For very low light,fast action situations, f/6.3 is pushing it. Overall, it is one of the best lens buys you can make and I highly recommend it.

Great lens designed specifically for digital SLR cameras with the smaller APS sized sensor, such as the Canon 20D or XTi have. I own many lenses, but this will now be my workhorse lens 99% of my photography. Only extreme wide angle or supertelephoto are outside its range, or alternatively when wide apertures are necessary. Not a pro lens, but an extremely good and useful consumer lens.

I have always been a Sigma fan when it comes to lenses, however the 18-200mm OS has been a real dissapointment to me. The sharpness of the picture has to be adjusted in photoshop to get a good clear picture. I even returned the first one I bought, and when they sent the second one it was the same. I have the 170-500mm Sigma and I love the quality shots it has produced, the same with Sigma's 10-20mm wide angle, very impressive. This lens I sold and bought a Canon IS lens instead. I will still buy Sigma but I am glad to be rid of this lens.