In that thread the pocket camera has much more IR problem than 4k camera. Pocket need IR filter also without ProND. 4K camera doesn't look like need IR filter with ProND. So probably F35 also don't need IR filter with ProND.
You have vimeo channel with F35 footage? I think hunter has a channel. I will look.
Or maybe I should just buy hoya IR cut filter and use my normal ND 4x4 filters? Don't know.
that holder is awsome but will a circle cover a 21mm cp , almost full frame , metabones speed booster ulta , fs7Q? thats the only reason why i think i gotta go 4 x 4.
Given your going almost full frame on a 21mm, I don't think a 4x4 will even cut it. I would think your going to need a wide-angle matte box and at least a 4x5.65.
Just to chime in - I have been using the ProNDs without a separate IR filter and did not notice IR contamination on the subject's black clothing. I'll see if I can grab a screenshot when I'm in the office Monday.