Create special effects
Add these filters to your kitbag to give your images a unique edge
At their peak, there were hundreds of different hardware filter types. Whatever special effect you wanted to create, there was a good chance that a filter was available to serve your purposes. Some were genuinely useful for professional situations, while others were gimmicky and questionably necessary.
Digital software filters have put an end to most of these, but there are still a few more unusual types that have a part to play in professional digital photography. This is potentially even more true in the current age of cross-genre content creation. For video shooting, there are effects which would take hours, if not days, to simulate on the computer, but which can be introduced with the addition of a single filter to the lens.