Sigma 18-200 for canon đánh giá
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The Sigma 18-200mm f/3.5-6.3 DC OS HSM is the latest in the company's long line of superzooms, which stretches back to the early 1990s and a series of 28-200mm (and later 28-300mm) lenses for 35mm SLRs. In fact Sigma was the first company to produce a superzoom for the burgeoning budget DSLR market, with its 18-125mm D3.5-5.6 DC of August 2004, followed shortly after by an 18-200mm F3.5-6.3 DC in February 2005. However the big problem with long, slow zooms is image blur due to camera shake, and in March 2007 Sigma duly announced this new version of the 18-200mm with the addition of 'Optical Stabilization' (OS) technology for Canon, Nikon and its own SD range of DSLRs (Sony and Pentax users, of course, benefit from sensor-shift image stabilization of all lenses). In somewhat curious fashion, the Nikon mount version also sports an ultrasonic-type 'HyperSonic Motor' (giving rise to the HSM tag,) while the Canon and Sigma mount models use a conventional micro-motor for focusing. Show Like all superzooms the Sigma 18-200mm OS features a complex optical design, in this case 18 elements in 13 groups including one Super-Low Dispersion (SLD) glass element, and no fewer than three aspherical elements to combat aberrations. A minimum focus distance of 0.45m through the entire range adds to the lens's all-round versatility. The optical stabilization system detects when the camera is panning and automatically switches to operating in one axis only, useful for shooting moving subjects such as sports. This lens competes directly in the 'stabilized superzoom' market with the Nikon 18-200mm F3.5-5.6G AF-S VR DX, Canon EF-S 18-200mm F3.5-5.6 IS, and Tamron 18-270mm F3.5-6.3 Di-II VC, all of which which we've reviewed over the past year. Its main advantage at the moment is that it is considerably cheaper than any of these other lenses, making it much the most affordable option for users looking to supplement their collection with a general-purpose travel lens. But in this case, does cheaper also mean inferior, or has Sigma delivered quality on a budget? Headline features
Angle of viewThe pictures below illustrate the focal length range from wide to telephoto (on Nikon DX format, 1.5x). Sigma 18-200mm f/3.5-6.3 DC OS HSM specificationsStreet price • $400 (US) • £280 (UK) Date introduced March 2007 Maximum format size APS-C/DX Focal length 18-200mm 35mm equivalent focal length • 27-300mm (1.5x DX) • 29-320mm (1.6x APS-C) • 31-340mm (1.7x Foveon APS-C) Diagonal Angle of view (APS-C) 74º - 8º Maximum aperture F3.5-6.3 Minimum aperture F22-40 Lens Construction • 18 elements / 13 groups • 1 SLD glass element • 3 aspherical elements Number of diaphragm blades 7, rounded Minimum focus 0.45m Maximum magnification 0.26x AF motor type • Micro-type Hypersonic Motor (Nikon mount) • DC Micro Motor (Canon & Sigma mounts) Focus method Internal Image stabilization • Yes • Automatic panning detection Filter thread • 72mm • Does not rotate on focus Supplied accessories* • Front and rear caps • Petal-type Hood Weight 600 g (21.2 oz) Dimensions 79 mm diameter x 98 mm length (3.1 x 3.9 in) Lens Mount Canon, Nikon, Sigma * Supplied accessories may differ in each country or area You may also likeMore about gear in this articlePhotokina 2006: Sigma has announced another digital-only lens, the new 18-200 mm F3.5-6.3 DC OS lens. This compact lens offers a big 11x zoom range in combination with Sigma's own Optical Stabilizer. Just like the 18-50 mm DC lens this one features aspherical and low dispersion elements as well as multi-layer coating to reduce flare and ghosting. On the downside it is slow (F6.3) at telephoto (you can't have everything at this price). On a digital SLR with a 1.5x FOV multiplier this lens provides an equivalent field of view of 27-300 mm on a 35 mm camera. Latest sample galleriesLatest in-depth reviewsThe Aura Carver 10.1" HD Digital Frame is a great way to put your portfolio on display and a great way to surface forgotten memories. The colors are vibrant, and the build quality is solid, but the Carver isn't without a few quirks. With a bigger battery and better video capabilities, the Fujifilm X-S20 could be the vlogging machine content creators have been waiting for. The Sony a7CR is a high-resolution addition to the company's compact full-frame a7C series. So what did we make of it and where does it leave the a7 IV that it sits just above? Lomography's LomoChrome '92 is designed to mimic the look of classic drugstore film that used to fill family photo albums. As we discovered, to shoot with it is to embrace the unexpected, from strange color shifts to odd textures and oversized grain. The LowePro PhotoSport Outdoor is a camera pack for photographers who also need a well-designed daypack for hiking and other outdoor use. If that sounds like you, the PhotoSport Outdoor may be a great choice, but as with any hybrid product, there are a few tradeoffs. Latest buying guidesIf you want a compact camera that produces great quality photos without the hassle of changing lenses, there are plenty of choices available for every budget. Read on to find out which portable enthusiast compacts are our favorites. What's the best camera for travel? Good travel cameras should be small, versatile, and offer good image quality. In this buying guide we've rounded-up several great cameras for travel and recommended the best. 'What's the best mirrorless camera?' We're glad you asked. What’s the best camera for around $2000? This price point gives you access to some of the most all-round capable cameras available. Excellent image quality, powerful autofocus and great looking video are the least you can expect. We've picked the models that really stand out. Above $2500 cameras tend to become increasingly specialized, making it difficult to select a 'best' option. We case our eye over the options costing more than $2500 but less than $4000, to find the best all-rounder. |
