1.  Field of the Invention
The present invention relates to a camera which is equipped with a device which reads information from a bar code provided on a film cartridge which is loaded into the camera; and more particularly relates to a camera in which countermeasures are provided against the possibility that the bar code signal should be undecipherable. 
2.  Related Background Art
A film cartridge is per se known (for example, refer to U.S. Pat.  No.  4,832,275) of a type in which the film is wound outwards from the cartridge or is rewound into the cartridge, respectively by the axis of a spool provided within the cartridge, on which the film is wound up, being rotated in a forward rotational direction or being rotated in a backward rotational direction.  When this type of film cartridge is loaded into a camera, a film forwarding device within the camera performs the film auto loading process by rotating the axis of the spool within the cartridge in the forward rotational direction so as to wind the head end or leading end of the film outwards from the cartridge in a pushing fashion, until the film leading end is caught by a takeup spool so as to cause the film to start to be wound up on the takeup spool. 
In U.S. Pat.  No.  5,023,642 there is, per se, disclosed a film cartridge provided with a bar code disk which rotates as a whole together with the aforementioned film spool, and on which there is inscribed in bar code form information relating to the film, such as the ISO sensitivity of the film and the number of frames available on the film.  With a camera using this sort of film cartridge, during the operation of film auto loading, the bar code is read by a photoelectric reading device which produces a signal representative thereof.  Subsequently it is necessary to decipher the bar code signal produced by this photoelectric device, in order to obtain the above described information relating to the film. 
However, it is not guaranteed that the film spool axis of this type of film cartridge is always rotated at an identical speed during the operation of film auto loading.  If for any reason an unevenness or irregularity should occur in the rotation of the film spool, i.e. in the rotational speed of the bar code disk, then there is a danger that it may not be possible to decipher the bar code signal read out by the photoelectric reading device from the bar code disk, so that accurate information relating to the film cannot be obtained.  Moreover, in the teaching of the above identified U.S. Pat.  No.  5,023,642 there is no suggestion as to what should be done in the event that the bar code signal should prove to be undecipherable, and because of this there is a danger that photography may subsequently proceed in an undesirable fashion without having obtained accurate information relating to the film, so that undesirable results may occur--for example over or under exposure of photographs taken on the film, mistaken frame counting, etc.