Definitely it has to be the Polaroid. The most popular types to use self-developing film were formerly made by Polaroid Corporation. The purpose of instant cameras served its usage for ID cards, passport photos, ultrasound photos, and other uses which required an instant photo. With the advent of digital photography, much of the instant camera's consumer appeal has been transferred to the digital cameras. Even most passport photo cameras have gone to digital, leaving instant cameras to a niche market.