I've searched but had no luck so I'm wondering if this exists.
A 4x4 frame that would hold a screw in filter in its center so that it be used in a mattebox
Maybe its a different frame for the standard threads 77mm, 82mm, 105mm, 110mm etc.
anyone know?
its a lot of work. You would get the Century 3X3 filter holder that takes series 9 filters and then get a screw filter to series 9 adapter. I'm pretty sure that you couldn't pull the filter tray out without unscrewing the screw in filter.
3x3 filters are roughly 77mm. I was able to pick up a 3x3 filter and use painters tape to hold it into my 4x4 holder. This could possibly work with a circular filter as well, but that would kinda limit that holder.. and you may get some vignetting from lenses with wider than 77mm filter rings. Anyways, tape worked well for me. It might work for you.
thanks for your responses, i have a 77 smoque 1 and a 77 soft fx1/2, figured i'm going to jury rig something to get these into a a 4x4
using a step up ring to help brace it in a piece of illustration card, fingers crossed