Whether you've bought a new camera and want to use your existing supply of filters, or somehow ended up with an incompatible combination, you might just get away with crafting your own filter adaptor using a household sponge, just as Sam Chapmans did for his Nikon 14-24mm lens.
Image: Sam Chapmans / The Rocket Factory
Chapmans ended up buying several neutral density filters, none of which fit his $US1700 Nikon lens. Turns out, no adaptor existed to fix one to the other and so, he was forced to come up with one himself.
Dubbed the "FX Sponge Filter Holder 5000", the adaptor is simply a sponge with an alcove carved into one side and a hole to slot the lens into. While Chapmans doesn't provide specific instructions you can follow to reproduce the final product, there are plenty of pictures to show you how it's done.