Two Filter Systems

• Cokin or Lee Filter Systems

This system uses square or rectangular glass or gelatin filters inserted into a filter holder mounted in front of the lens.

Advantages:
– Can be used on several lenses with different filter diameters (only the adapter ring needs to be changed).
– Easier to use when stacking multiple filters together.
– Allows precise placement of the horizon line when using graduated filters.

Disadvantages:
– Does not fully protect the front lens element. Water or dust may enter from the sides.
– Bulkier and less discreet.

• Circular Filters

A circular filter is a round glass filter that screws directly onto the lens filter thread.

Advantages:
– More compact and discreet.
– Fully protects the front lens element.

Disadvantages:
– Less convenient to remove and reattach.
– A filter only fits one specific diameter. New filters must be purchased for each lens size.

One Circular Filter for Multiple Lens Diameters

There is, however, a way to avoid buying and carrying multiple circular filters: using adapter rings.

These adapters make it possible, for example, to use a 52mm filter (common on vintage Nikon film cameras) on a lens with a 49mm filter thread (common on vintage Pentax film cameras).

The savings can be substantial, and carrying a single set of filters is far more practical.