This is a SIGMA lens that has a 0.5-metre minimum focusing distance and a 56 mm maximum focal length. The filter size for this lens is 55 mm, so make sure the filters will fit.
From London Camera Exchange
Sigma 56mm F1.4 DC DN Contemporary - For Micro Four Thirds
Camera Centre
Sigma 56mm F1.4 DC DN Contemporary Lens: Micro Four Thirds - A GRADE
This product is also available at 3 unverified stores.