They are precise in depicting exactly what is there or what is being imagined.
Idealism deals with making things more beautiful than they are or more beautiful by standards.
Abstract art eliminates all but the essentials. It also uses more simplified shapes. Photography is accepted to be something that only shows what is truely real. Painting may portray something that is no-existant or it may exaggerate or underestimate something. Fort Peck Dam, Montana.1936 to Thomas LeClear.