Most motion pictures made in the second half of the 20th Century were made with 35 mm film and cameras. Because these cameras have been used so frequently and for so long, this is the most readily available type of film camera and it is the camera that the most information is known about. Most of the how-to books and film theory books available will deal primarily with 35 mm film and cameras.
With its larger format, 70 mm (or 65mm) film provides higher resolution than 35 mm and, until digital sound was introduced for 35 mm cameras, it had better sound. The larger format also means that 70 mm is most commonly used for specialty projects, such as iMax and three-dimensional (3-D) films. On the downside, it is more expensive than 35 mm and many theaters do not have the facilities to show 70 mm movies.
Digital cameras are becoming more popular because shooting in digital is considerably less expensive. Digital cameras only need memory or digital video tape, not film. It is also easier to edit movies shot using digital technology as they can be directly uploaded into a computer and are easier to edit. Many find digital images too sharp though and much more care must be taken with lighting and other effects.