At least one of an error detection code for detecting an error in information to be recorded and an error correction code for correcting the error in the information is added to the information, and the information with at least one of the error detection code and the error correction code added thereto is recorded in a magnetic recording section provided in a photographic film. The information recorded in the magnetic recording section of the photographic film is read, and at least one of the detection of an information-reading failure and the correction of the error in the information is effected on the basis of at least one of the error detection code and the error correction code added to the information which has been read.

A magnetic recording device of a camera is driven, while a photographic film is advanced by one frame by a motor, to record photographic data on a magnetic recording layer of the film. A current flowing through the motor contains a periodically changing ripple signal. The ripple signal detected by a ripple detector is converted into ripple pulses by a wave-shaping circuit. The ripple pulses are supplied to a prescaler which generates one prescaler pulse each time a predetermined number of ripple pulses are counted. A timing signal is generated at the period obtained by multiplying the prescaler pulse period by a coefficient K. One bit data is read in response to the timing signal and recorded on the photographic film. The coefficient K is calculated each time one frame advance is completed, and is used for the next frame data record. In a preferred embodiment, a rotary member is fixed to the rotary shaft of the motor. A photosensor detects the rotation of the rotary member and generates pulses to be supplied to the prescaler.

In a magnetic recording apparatus for a camera using a film having a magnetic recording portion, a magnetic recording device records photographic data on the magnetic recording portion while the film is wound after a photographic operation corresponding to one frame is completed. An electrically erasable nonvolatile storage device stores the photographic data after the photographic operation corresponding to one frame is completed. A magnetic reproducing device reproduces the photographic data recorded on the magnetic recording portion while the film is rewound. A determining device determines whether the photographic data reproduced by the magnetic reproducing device coincides with the photographic data stored in the storage device. When the determining device determines that the two photographic data do not coincide with each other, a re-recording device causes the magnetic recording device to re-record the photographic data stored in the storage device on the magnetic recording portion. An erasing device erases the magnetically recorded data when the determining device determines that the two photographic data do not coincide with each other.

In photographic equipment for reading magnetically recorded data on a film strip, gradual degradation of the read data signal caused, for example, by material buildup on the magnetic read head is detected by monitoring the read data signal to indicate when the signal falls below a normal signal level but is still above a minimum threshold at which data loss would result. Apparatus useful for this purpose includes first and second comparators for sensing the decline of the data signal level into a range falling between a first predetermined normal signal level threshold and a second lower predetermined signal level preferably at or slightly above minimum detectable signal level. With such an arrangement, even though data is still capable of being read and decoded, the operator of the data read equipment is given advance warning of the incipient read data problem sufficiently in advance of read failure condition to allow corrective action, e.g. cleaning of the read head, before actual data read failures occur.

A photographic camera is provided with magnetic recording means including a frequency selection circuit responsive to a controller to iteratively record data on a magnetic recording layer formed on photographic film with each iteration being recorded at a different recording frequency. Suitable selection of recording frequencies for a range of expected film speeds will result in a predetermined number of recorded iterations for which respective bit densities and cumulative recorded track length will fall within predetermined acceptable limits established for reliable reading of the data by subsequent data read circuits.