A kind of on-screen spirit level that shows you when the camera is level. This can be useful in landscape photography, for example, when the horizon isn’t flat or visible. Some also have fore-and-aft levels to help avoid any tilt (and converging verticals) when shooting buildings.
These are an option on both DSLRs and in electronic viewfinders. You can use the grid to make sure horizons are level and buildings are vertical – some grids confirm to the ‘rule of thirds’ to help you get a satisfying composition.
A ‘rule’ of composition that says that pictures look best if objects are placed one-third of the way in from the edge or top/bottom of the picture, rather than being placed directly in the centre. It can be helpful, though calling it a ‘rule’ gives it more importance than it deserves.
Where the shot is taken with the camera held horizontally – pictures are wider than they are tall.
Trimming images to remove unwanted detail at the edges or make them fit the aspect ratio of screens or specific printing papers or to improve the composition of a photo.