Sigma 18-200mm F3.5-6.3 II DC OS HSM Zoom Lens Review Roundup

On October 10 2011, Sigma announced the 18-200mm F3.5-6.3 II DC OS HSM high zoom lens, an update to their original 18-200 DC OS HSM lens first introduced in 2007.  This 11.1x high zoom ratio lens is designed exclusively for DSLR cameras, incorporates Sigma's original OS (Optical Stabiliser) function and offers a broad shooting range from wide angle to telephoto. The lens features new FLD glass elements, and SLD elements for improved optics, while Sigma's Super Multi-Layer Coating aims to help reduce flare and ghosting. Here's the technical specifications:

The new lens is available for Sigma, Canon, Nikon, Pentax, and Sony mounts, though on Pentax and Sony mounts, there will be no included optical stabilization ("OS"). Note that the "DC" means that the 18-200mm F3.5-6.3 II DC OS HSM is for non-fullframe APS-C DSLRs cameras. The lens is listed for retail at $720. Here's the lens review roundup:

ePhotoZine, gave a rating of 3.5/5: "As is the case with many high zoom ratio lenses, sharpness levels are very high at shorter focal lengths, dropping as the lens is zoomed in. At 18mm sharpness in the centre of the image area is outstanding from maximum aperture, dropping due to the effects of diffraction as the lens is stopped down. Sharpness towards the edges is very good at this focal length and remains so until the lens is stopped down to f/8. Zooming to 50mm results in a reduction of overall sharpness. At maximum aperture the clarity in the centre is still very good, but the quality towards the edges falls below good levels. Sharpness towards the edges increases as the lens is stopped down with peak quality being recorded between f/5.6 and f/11 for this focal length. Finally, at 200mm sharpness in the centre of the frame remains very good, with a further reduction in quality towards the edges of the frame. Peak quality for this focal length is achieved at f/11. Chromatic aberrations rise and fall as the lens is zoomed through the range. At 18mm and 200mm CA levels are quite high towards the edges of the frame and may become apparent in large prints with areas of high contrast near the edges.  Falloff of illumination towards the corners is reasonably well controlled. At 18mm the corners are 1.49 stops darker than the image centre and at 200mm the corners are 1.3 stops darker. Visually uniform illumination is achieved with the lens stopped down by just over a stop from maximum aperture throughout the zoom range. Distortion is often a weakness of high ratio zooms like this. Although the 3.45% barrel distortion at 18mm is quite strong, it isn't all that bad when compared to some similar lenses. Pincushion distortion of 1.61% is present at the telephoto end, which shouldn't pose too many issues for most. If you require completely straight lines, you'll be glad to know that the distortion pattern is uniform across the frame throughout the zoom range, which should make correction in image editing software relatively easy to apply. A petal-shaped hood is supplied as standard with the lens, which does a reasonable job of protecting the front element from extraneous light that may cause unwanted flare and loss of contrast. During testing there were no issues with flare and contrast holds up well, even when shooting into the light.

This 18-200mm Sigma lens includes optical stabilisation and costs around £340. Tamron's 18-200mm XR Di II costs much less at £175, but lacks optical stabilisation, which can be especially useful given the modest f/6.3 maximum aperture both lenses sport at 200mm. It also lacks the silent focusing motor, as found on the Sigma lens. The Canon 18-200mm f/3.5-5.6 has a brighter maximum aperture at 200mm, supports full time manual focus override and also includes an image stabiliser, but costs around £420. Nikon's 18-200mm f/3.5-5.6 VR II lens is much more expensive at around £590 and sports similar features to the Canon 18-200mm. As the Sony compatible version of this Sigma lens doesn't include optical stabilisation, Sony's 18-200mm is almost exactly similar in specification, except for the Sony lens lacking a silent focusing motor. Being priced at around £450, it's around £100 dearer that the Sigma lens too. With the price being around £100 less than comparable competition, this lens represents very good value. For a lens of its type, it produces images with decent sharpness throughout the zoom range, plus it is lightweight and well built. If you're on the hunt for a convenient super-zoom, this lens may well be worth consideration due to its good performance for the price."... [Source]

PopPhoto: "Noticeably lighter and more compact than the earlier version, the new zoom is more than a half-inch shorter at all focal lengths, and several ounces lighter. It takes 62mm filters, down from 72mm. Like the older lens, it is compact enough to cast no shadow at any focal length or focusing distance when used with our test camera's built-in flash. Our test sample's unusually loose zooming action produced significant zoom creep when the camera/lens rig was aimed up or down. This can cause future focus and composition issues, especially if the zoom helical gets looser with age, as such things are wont to do. The barrel lock has little use here, as it can only be engaged at the lens' contracted 18mm focal length setting. But this isn't to suggest the lens suffers from what manufacturers call "slop." Like its older brother, construction quality is high, with rugged switches and rings--it feels solid. The turning radius for the manual focus ring is short (60 degrees), so unlike the Rokinon tested this month, its subject distance scale is practically useless for low-light scale focusing. However, the Sigma's barrel-top macro scale ranges from 1:3.8 to 1:13.2, and might appeal to close-up shooters. Nearly silent and satisfyingly fast, the HSM focusing motor is a welcome improvement over that of the older lens, which we described in our October 2007 test report as "moderately fast and somewhat noisy."

On our optical bench, the new lens turned in Excellent-range SQF numbers at all four tested focal lengths. This is great for an all-in-one zoom, as most in this class dip into the Very Good sharpness range at at least one focal length. (And Nikon's 18-200mm dipped past Very Good into the Good range at 200mm.) Ironically, the heralded incorporation of Sigma's special FLD glass seems to have produced the opposite of the intended effect: Despite the FLD element, Version II's performance numbers were slightly below those of Version I's at our 11x14 benchmark magnification, though all were in the Excellent range. The new lens' distortion control proved problematic, as well. The earlier lens produced Visible-range barrel distortion (0.57% at 18mm) at only one of the four tested focal lengths, and Slight-range pincushion distortion at the three other (longer) zoom settings. The new lens did the opposite: Three of four focal lengths produced less-than-desirable Visible-range distortion, and only one (200mm) rose to Slight. In its defense, the new version's 0.54% barrel distortion at 18mm, while rated Visible, nevertheless represents a best-in-class performance of comparable tested lenses. Sigma's fall-off-free corners at three of four focal lengths and its maximum 1:2.63 subject magnification also won it best-in-class ribbons. If you're shopping for an all-in-one, take a look at this Sigma. While it's slower at the long end compared to similar glass, it's significantly less expensive and in many ways optically superior."... [Source]

LensTip: "Perhaps the most important question this review should answer is whether the new model of the tested lens is better than its predecessor. The answer seems to be positive. The resolution of the new lens is similar to that of the older model; the chromatic aberration, distortion on wide angle, coma and astigmatism decreased. The vignetting and work against bright light got worse but it was compensated by adding an HSM motor, more efficient stabilization and noticeable decrease of physical dimensions which made the Sigma 18-200 mm OS II the smallest lens of this class available on the market. Overall, there are definitely more steps forward than backward. Compared to its rivals, the Sigma shouldn't be ashamed of anything. It is definitely better than the Canon 18-200 mm IS. The Nikkor 18-200 mm VR represents more or less the same quality of optics; it is faster but also more expensive. It should be emphasized that the suggested price of the Sigma is hardly low. 2000 PLN for a 18-200 mm megazoom lens is steep but its predecessor, when launched on the market, had a price tag even by 200 PLN higher. Here Sigma also took a step in the right direction.

The most serious competitor of the Sigma seems to be the Tamron 18-270 mm VC. It is a lens which fares decently well, being equipped with an image stabilization, having a wider range of focal lengths to boot; it is also by 100-200 PLN cheaper than the Sigma. Assuming that the current price of the Sigma is so high just because it is still a novelty on the market and after several months it might decrease, even if only slightly, it might become a very interesting option for amateurs of this kind of equipment. They might be tempted not only by good performance but perhaps mainly by small dimensions which are important to megazoom users as they often take their lenses with themselves on trips and journeys."... [Source]