Graduated filters are clear at the bottom but darkened at the top, with a smooth, graduated blend in between. You use them in landscape photography to tone down bright skies without affecting the land. You can also create graduated filters ‘digitally’ in image-editing software.
Camera (lens) filters
Filters are still useful for toning down bright skies, saturating colours or just protecting our lens. Here's some more information about filters, types and tips. Photo by Christian Fregnan on Unsplash
This is a fine screw thread cut into the front of almost all DSLR and mirrorless camera lenses. This is where you screw in glass filters, or the adaptor rings for square filter holders. The size of the filter thread varies, so make sure you buy filters or adaptors the right size for your lens.
Most filters these days are designed as modular filter systems consisting of a square filter holder with slots for three rectangular filters and, sometimes, a circular polarising filter too. The filter holder attaches to the camera lens via an adaptor ring. In this way, the same filter holder and filters can be used with many different lenses.
This can mean the filters you attach to the front of the lens to change the appearance of the picture, or software filters that do the same thing on your computer.
A colour filter used in black and white photography to change the shade of grey that colours are reproduced as. They’re called ‘contrast’ filters because they can change the contrast (in shades of grey) between different colours.