I've had this lens for a while and although I've sold it it's actually pretty good value for money. Anyone expecting a professional 2.8 lens at this price is going crazy. The first thing you'll notice is that the build quality is super plastic, even toy-like. That put me off but to get a better lens you have to pay hundreds if not thousands, the Nikon 55-200 alternatives are also plastic and Sigma doesn't offer a 55-200. in EX version. However, the Sigma 55-200 does have some merits if you're not too concerned about brand name appeal. Due to its short barrel, it autofocuses very quickly and its light weight makes it excellent for handheld tracking of moving subjects. and the optics are clearer and sharper than you might think, although there's a slight dip at 200mm. This lens will obviously appeal to photographers on a budget, but it's also a good travel spare for those who don't want to lug around a lot of heavy glass. and for the price offered you can easily buy two in case one breaks. Note: Unfortunately for d40 users, the Sigma 55-200 does not have an internal motor, so your camera will not auto-focus with it.
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