Originally Posted by frobozz
Can't you just use a standard 4-inch filter holder like they use in movies/TV? Of course the filters are pricier, but if it's just for the one filter for IR work...
Gee, even Nikon seems to make one:
I honestly didn't know Nikon made those!
I like the idea of using an accessory viewfinder. The old turret finders are pretty awesome.