I have had this wonderful lens for sometime but I am never able to use it because I love using filters but this lens has no standard way of fitting a Lee or Cokin Filter holder. I know Lee will be launching a new filter system for this lens in June but I am a very inpatient person and I think it will be over £300+VAT just for the holder and maybe 1x filter! So I was thinking I can make one for much less and still decent quality. and it can take the 130mm / 170mm Grad filters that Lee & Cokin Make. below is a list of key ingredients you will need.
thin Black plastic sheet / or black card
Thin foam + spray adhesive
I have posted some photos of my filter holder below, I have only had a quick test and there is no cut off at 16mm on a FX Camera so a DX would be ok for sure.
I am going to head out tonight and get some landscape test shots so will post the results later.