Photometry device that detects and compensates for an inversion abnormality

A photometry device comprising:

• a photometric circuit that performs photometry on an object field using an accumulating photometric element;
• an abnormality sensor that determines whether an inversion has occurred in an output of the photometric circuit by determining whether the photometric circuit output has dropped below an overflow condition after the photometric circuit output has first reached the overflow condition;
• and
• a controller that controls the accumulation of charge by the photometric element of the photometric circuit based on whether the abnormality sensor determines that the inversion has occurred in the photometric circuit output.

A photometry device comprising:

• photometric means for performing photometry on an object field based on an amount of charge that is accumulated due to exposure by light from the object field with the passage of time;
• abnormality sensing means for determining whether an output of the photometric means is normal or abnormal, the abnormality sensing means determining that an abnormality has occurred when an inversion, which is a drop in the photometric means output below an overflow condition after the photometric means output has first reached the overflow condition, has occurred;
• and
• control means for controlling the accumulation of charge by the photometric means according to a first process when the abnormality sensing means determines that the output of the photometric means is abnormal, and according to a second process differing from the first process when the abnormality sensing means determines that the output of the photometric means is normal.

A method of controlling photometry comprising the steps of:

• performing photometry on an object field using a photometric circuit that accumulates charge with the passage of time;
• determining whether an output of the photometric circuit during the photometry was normal or abnormal, the output of the photometric circuit being determined to be abnormal when the output of the photometric circuit drops below an overflow condition after the output of the photometric circuit has first reached the overflow condition;
• and
• controlling the accumulation of charge by the photometric circuit during a subsequent round of photometry according to a first process when the photometric circuit output is determined to be abnormal, and controlling the accumulation of charge by the photometric circuit during the subsequent round of photometry according to a second process when the photometric circuit output is determined to be normal, the second process differing from the first process.