If your novel has already sold the film adaptation rights, then your novel adaptation rights have already been authorized to be used to make a movie. Therefore, if you want to use the novel adaptation rights to make a microfilm, you need to get another authorization. Usually, the adaptation rights were independent, which meant that you could freely adapt the novel into a microfilm without first obtaining the authorization of the film adaptation rights. However, due to legal and commercial reasons, there may be some restrictions and conditions on the transfer of adaptation rights. Therefore, if you want more detailed information, it is recommended to consult a professional lawyer or copyright agent. In short, if your novel has already sold the film adaptation rights, you can continue to sell the microfilm adaptation rights, but you have to abide by the relevant laws and business regulations.