PURPOSE: To execute the operation at a high speed by separating input data into a first data part for showing a digit of a reference bit or above and a second data part for showing a digit of under the reference bit, and setting a reference value as a value of a second data part in the case the value of a second data part exists.
CONSTITUTION: The device is provided with DX pins 1, 2, 3, 4, and 6 being a data input part, a data rounding means 7 for rounding the data detected from a conducting state of these pins and setting the film sensitivity, and an arithmetic means 10 for executing an exposure operation, based on this output. The Dx pins 2, 3 and 4 detect a first data part, and as for a value of a second data part of under a reference bit, '0' or not is detected from an output of the pin 6. In the case there is a value of under the reference bit, a value of a second data part is set to a 1/2 step of a first data part in the data rounding means 7. In this case, errors at the time when an elimination bit is effective and invalid are distributed mutually, an exposure error becomes a 1/6 reference value bit and the accuracy is compensated. In such a way, the arithmetic time efficiency is improved.
HOSOKAWA TETSUO
TAKAMI SATOSHI
