I bought a "EX+" sigma non-DG 170-500mm lens from one of the two big photo gear shop used department, and not only was it poor condition with a front lens blemish and scratches over the lens body, but it did not focus to infinity (tested with live view) nor zoom smoothly. At least they paid for return shipping and returned it no question asked. I saw a BGN 170-500mm lens at KEH that had no tripod collar for 100 bucks less than what I paid for at that other store, and when it arrived not only was the lens in almost perfect condition it was the DG version! Now I have a 100 bucks extra to spend on either neoprene lens cover or a tripod mount. Is the TS-21 the original collar for the lens? Will the sigma TS-41 fit? Are their any other cheaper alternatives? If I pay 150 for a tripod collar it will be more than 50 percent of what I paid
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