Electric flash lamp unit with a light controlling circuit

A flash terminating signal generating circuit comprising:

• means for generating clock pulses;
• means for counting the clock pulses in response to a flash starting signal;
• memory means for storing a plurality of time data corresponding to a flash time of an electric flash lamp in a plurality of memory locations with corresponding addresses;
• means for measuring information of a distance from a flashing point to an object illuminated by flash light;
• means for converting the distance information supplied from said measuring into first address data, supplying the first address data to said memory means, thus designating one of the addresses of said memory means, and reading a respective time data from the memory location thus designated;
• and
• means for comparing the time data read from said memory means with the contents of said counting means and producing a flash terminating signal when both the time data read from the memory means and the contents of said counting means are coincident with each other.

An electric flash lamp unit for energizing an electric flash lamp by supplying the lamp with energy stored in a capacitor, comprising:

• means for detecting a voltage charged in said capacitor to produce a charge voltage signal;
• means for modifying the charge voltage signal supplied from said detecting means with a film sensitivity and an F number;
• and
• means for comparing the modified charge voltage signal with a reference signal containing distance information and producing an alarm signal.

An electric flash lamp unit for energizing an electric flash lamp by supplying the lamp with energy stored in a capacitor, comprising:

• means for detecting a voltage charged in said capacitor to generate a charge voltage signal;
• means for modifying the charge voltage signal supplied from said detecting means by a film sensitivity and an F number;
• and
• means for decoding the modified charge voltage signal from said modifying means into distance information and displaying the decoded distance information as a maximum photographing distance.