The third precept in Buddhism is not to engage in wrong sexual behaviour. The Buddha accepted that it is legitimate for lay people (not monastics) to indulge and enjoy the pleasures of the senses, he pointed out that sensual desire is a hindrance to mental calm and weakens wisdom. Buddhism is not about whether an action is sinful but rather whether is helps or hinders one in the quest towards the state of nirvana. Use of pornography is therefore frowned upon by Buddhists, also because it most often involves the exploitation of other human beings.
