Sigma 18-50mm f/2.8 DC DN Contemporary: B&H Photo / Amazon / Adorama A Sigma 50-135mm F2.8 DC DN patent was found by asobinet and while most patents do not become lenses this could be a useful 3rd party 70-200mm full frame equivalent lens to compliment the popular Sigma 18-50mm f/2.8 DC DN Contemporary. overview [Publication number] P2023179307 [Release date] … Continue reading Sigma 50-135mm f/2.8 DC DN Patent Found