I don't know that I'd bother with one, unless you were using the Anafi sitting on something & not in the air. If you had a shutter speed of say 1/1250 that would then equate to a 0.8 second long exposure, which the Anafi just isn't that stable to achieve a crisp image, unless it's not flying.
If you did work with it stationary, I would suspect you'd achieve some quite good DNG images, if the glass of the filter wasn't producing too strong a colour cast, but that can always be minimised in post-production.