The next thing before using the X4 Circular Polariser was to open the box to see what was included in the package.
A very nice microfibre cleaning cloth is placed on top of the filter case. The red bold text “WARNING” catches my eyes.
The warning prompts me to look for instruction immediately underneath. But it is strange that there is nothing except the filter inside the case (the case reminds me of the B+W filter case). In fact the instruction is written clearly on the box after searching from top to bottom.
By following the link and typing in the URL on a browser, you are redirected to Breakthrough Photography activation page and asked to select the filter type, enter your name, email and the serial number of the filter. Where is the serial number? It is engraved on the filter rim.
At the end I reached this page and the activation was successful.
It was that easy.
The image featured in this post was taken with the Leica M and the Summicron-M 50 mm f/2.0.