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Title: Great teleconverter
Review: I've been using this teleconverter with my Sigma 70-200 2.8 lens, and it works like a charm, exactly as advertised with, as far as I can tell so far, no degradation in image quality. I'm sure there is some (don't think you could get it to zero), but it's not noticeable to my eye, and I've been known to do some pixel peeping. The build quality is solid, as with all my other Sigma lenses.Just don't forget that this adds a stop to your lens, so my 2.8 is a 4 with it on. Also, be SURE to check compatibility charts at Sigma before you buy it!
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