Canon Kabushiki Kaisha

Takayuki Saeki

Koji Takahashi

Hiroyuki Takimoto

Isao Harigaya

Kazumitsu Tobe

It is an object of this invention to provide an image pickup apparatus capable of suitable appropriate exposure control even when objects having extremely different luminance contrasts exist at the same field angle. The invention provides an image pickup apparatus including an integral circuit and a control circuit. The integral circuit calculates an average value a of photometry luminance integral data of all of m&times;n divided photometry frames, and an average value a of photometry luminance integral data of x divided photometry frames sampled in descending order of luminances from the m&times;n divided photometry frames. When the difference between the average values a and a exceeds a predetermined threshold value z, the control circuit performs correction of decreasing an appropriate target value of exposure control in accordance with the value of (a a ).

Exposure control of an imaging apparatus using a plurality of photometry frames

A remaining-amount-of-battery detecting device according to the present invention detects the remaining amount of battery power. The device is arranged to measure the open-circuit voltage of a battery and detect the remaining amount of battery power on the basis of the measured open-circuit voltage of the battery, so that it is possible to accurately detect the remaining amount of battery power.

Remaining-amount-of-battery detecting device

Device for detecting the charge condition of a battery which measures the first output of the battery when connected to the first load and the second output of the battery when connected to the second load, and performs a predetermined computation on the basis of both the first and second outputs of the battery to detect the charge condition of the battery. The charge condition of the battery can be very accurately detected.

Battery charge detecting variable loads

A charging apparatus for charging a secondary battery, arranged in such a manner that the terminal voltage of the battery being charged is measured and then correlated with remaining charging time and usable time of the battery being charged. The remaining charging time and usable time of the battery being charged is stored in memory and then outputted for display to the operator.

Charging apparatus

A charging apparatus for charging a secondary battery arranged in such a manner that the interterminal voltage of the battery, which is being charged, is measured so that the charging status of the battery is detected in accordance with the measured interterminal voltage of the battery which is being charged and the charging/discharging characteristics with respect to the interterminal voltage of the battery. As a result, the charging status of the battery can accurately be detected.

Growing community of inventors

Kanagawa-ken, Japan

Takayuki Saeki