Five things to look out for

1

A circular ND filter is ace – as long as you only want to use it with one lens thread diameter.

2

While they need both a holder and an adaptor ring, square ND filters can be used with multiple lenses.

3

To shoot minimalist land-, sea- and cityscapes, you’ll need a dense 10-stop filter to slow your shutter speed.

4

While colour casts can be corrected in editing programs, fuzziness from poor glass quality will be impossible to fix.

5

A square ND system opens up possibilities for stacking filters such as a polarizer or graduated ND filters.