Sigma 18-200mm f/3.5-6.3 11 DC OS HSM Lens for Canon

Product Information

I know many L snobs say this is a junk lens but I guess they never ever shoot in Burma or Cambodia with a white lens , to see how the local people there react to their white Ls. Set to 18mm, wide-angle performance is good wide open at ƒ/3.5 (sharp in the center, mdoerately soft in the corners), becoming excellent as you stop down to ƒ/5.6, where it is essentially sharp across the frame. Diffraction limiting begins to set it at ƒ/8, though it doesn't impact on sharpness until ƒ/16; even at ƒ/16, we're seeing only 2 blur units across the frame. Using the ƒ/22 aperture setting produces a softer image, at 3 units across the frame. UPDATE: after posted this one , I read the previous poster's trashing this lens , and I thought he probably never used this lens in real life or he just got a bad copy. In any case , this lens is much better than that , it's AF very fast ,at least as fast as any other consumer grade lens in this price range and actually faster AFing than the Nikon super zoom , which I also have had for about 4 months. These trips gave me a very good opportunity to put the combination to use in the field along with typical use around home and testing in the studio. Although this lens isn't the cheapest of the bunch, the good build quality and optical performance will certainly make this a compelling choice when compared to the competition.

The new product lines incorporate rubber for the attachment part of the provided lens hood. For better usability, the design of the lens cap and AF / MF changeover switch has been improved. If we compare the specifications of the Sigma 18-200 mm C with those of other superzooms, then the Sigma 18-200 mm C offers more close-up than the competition. Tamron's comparable offering is similar to the Canon 18-200mm as well, however, the 18-200mm Tamron does not feature image stabilization. The Canon shows off much better results in sharpness and resistance to chromatic aberration, but the Tamron shows slightly less corner shading, and slightly better distortion control. The Tamron's minimum aperture at longer telephoto lengths is ƒ/6.3, compared to the Canon's ƒ/5.6.

Weighing 595g, this lens isn't overly large or heavy for one that covers such a range and it balances extremely well on the EOS 7D used for testing. Build quality is good, with much of the lens barrel being constructed from high quality textured plastics, typical of Canon's higher-end EF-S lenses. The lens mount is metal and as it is an EF-S has a baffle protruding from the rear to prevent mounting of the lens on incompatible cameras, such as the EOS 10D. The focal length decrease (which does happen in this and many other close-focusing zooms; if you are feeling skeptical do some comparisons at different distances with fixed focal length lenses--shortening the focal length is one way of getting higher reproduction ratios with the same lens extension, and clearly zoom manufacturers take advantage of this) can be annoying if trying to shoot telephoto shots of, for example, small birds at relatively close ranges. By my rough estimation, for example, at about 10 feet the field of view is about the same as that of a 125mm fixed-focal-length lens. You only get the real 200mm at near-inifinty distances. With lateral chromatic aberration, not all colors come out in exactly the same place in the corners of the image, so that you can find blue and red edges at sharp contrast transitions in the corners. The Nikon D7100 corrects for this outstandingly, so that you don’t encounter any visible chromatic aberration in the jpg files. In the RAW files, chromatic aberration, just as with all other superzooms, is visibly present. That’s simple to correct with software. The real minimum focal length is somewhat understated by Sigma, coverage at "18mm" falls almost exactly between the 18-70 Nikkor and my 20/2.8 fixed focal length Nikkor so I would guess it is really about 19mm. Of course, accurate focusing is not especially challenging for a slow (narrow aperture) lens on a 1.6x body.

Shooting wide open at 18mm, sharpness in the centre of the image area already approaches very good levels, and clarity towards the edges of the frame is fairly good. Stopping down the aperture improves sharpness across the frame, peaking between f/5.6 and f/8, where sharpness in the centre is excellent and towards the edges it reaches very good levels. Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimize the problem, hence they usually cost more.The range is a bit cramped at the shorter end, making it less easy to set precise framing. It's fine throughout the rest of the range. AF operation is fast enough, and not too noisy, but I found it to be sometimes inaccurate at 18mm. This problem dissapears when I use the center AF sensor only (not a big deal for me). Where do I start... This lens gets the most action/time on my camera. Images are clear and color accurate and the zoom range makes it hard to take off. I am a 1:1 ratio person that hates photos that only look good from far. I try for that pixel to pixel perfection that makes my hobby harder, but so much more enjoyable when done right. I don't use or run photos thru photoshop, because a part of me thinks it is cheating (leads me to retake photos often). I suppose someday I will change, but until then, I want a simple and clean photo.