I have Hex 57mm 1.2 (AR) and an EM-5. the adapter is not here yet....just trying to get some homework done prior to. I can not select "57mm" with the EM-5 (IS+Info). The closest choice is 55mm. What is the consensus with this situation? Go with the EM-5's "55mm" choice or turn off IS? Thanks, Paul also... i read Radioactive lenses - Camerapedia ) that some manufacturer's of these "hot" lenses used up to 30%(by weight) of thorium oxide while others used lanthanum with thorium mixed in. these lanthanum based lenses can be 1/10 000 less radioactive. anyone know what category our lovely Hex AR 57mm 1.2 belong to (mine is s# 7509xxx).