From Gehr

"A still has to do with a particular intensity of light, an image, a composition frozen in time and space.
A shot has to with variable intensity of light, and internal balance of time dependent upon an intermittent movement and a movement within a given space dependent upon persistence of vision...
A still as related to film is concerned with using and losing an image of something through time and space. In representational films sometimes the image affirms its own presence as image, graphic entity, but most often it serves as a vehicle to a phot0-recorded event. Traditional and established avant-garde film teach film to be an image, a representing. Bu film is a real thing and as a real thing it is not an imitation. It does not reflect on life, it embodies the life of the mind. It is not a vehicle for ideas or portrays of emotion outside of its own existence as emoted idea." (Ernie Gehr, Programs Notes, Film Culture no. 53-55 (Spring 1972)