Photography is often real looking- realism in painting must therefore look close to life.
Nonobjective abstraction is as far away from realism as possible, nothing real can be identified.
Abstraction then is created in the following ways...
Abstract color- the color challenges the realism, it is non realistic.
Abstraction through simplification- it is an obvious design or it is a super close photograph.
Abstraction through distortion.
Abstraction through fracturing.