The filter thread size of Panasonic Leica DG Macro-Elmarit 45mm F2.8 ASPH OIS is 46mm.
Below are links to the filters that we recommend you to consider for your Panasonic Leica Macro 45mm F2.8 OIS:
Read our detailed Panasonic Leica DG Macro-Elmarit 45mm F2.8 ASPH OIS Review