http://www.nikonchat.com/tamron-nikon-18-200/
What is recommended to target someone for Nikon D200, Nikon 18-135, Sigma 18-200, Tamron 18-200?
From your list – while I, as buy Nikon lenses for Nikon cameras – the new Sigma 18-200 "OS" lens is a good choice. No, I said "operating system" (Optically stabilized), but put it in this country, the goal very well and has revised the "operating system is" a great advantage. The lack of "system operating "Sigma 18-200 seems to find favor with users who examined him at B & H Photo, too, but I have not read a professional review of the lens. If you are curious about the range of 18-135 18-200 vs one, check out this page: http://www.flickr.com/photos/7189769 @ N04/476181737 / This was done with two different lenses : the Nikon 17-55 and 70-300: http://www.flickr.com/photos/samfeinstein/1245831147/ You should look at the actual focal length and no effort (equivalent) of coordination, the test was conducted on a D200 like yours.
Objektivtest: Tamron AF 18-270 mm F/3.5-6.3 XR Di II VC LD vs. nikon 18-200 vr
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