This SIGMA-made lens is equipped with auto focus to give you the best setting for each picture. If you want to use a filter on the lens, then the filter size is 55 mm.
From London Camera Exchange
Sigma 18-50mm F2.8 DC DN Contemporary - For Sony E
Camera Centre
Sigma 18-50mm f2.8 DC DN Contemporary Lens - Sony E Mount - EX-DEMO
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