As a model sometimes you will go on a job for a photographer that does not include a client so you are just basically working for the photographer who will then sell or do what ever he wants with the pictures, sometimes you work out a deal with him where you will earn some back end money if the pictures sell.

You as the model though should always make sure to get a copy of the pics, some photographers are really good at making sure you get copies because you worked as hard as he did and I have met some that years later I am still trying to get a copy of my work, when that happens though usually that photographer gets a really bad reputation, and in this industry reputation is EVERYTHING.