Patent ID: 6928240

Claim:
A camera comprising: light emitting means that projects a beam of light onto an object to be measured; light detecting means that detects the light projected toward and reflected from the object at a light detecting position corresponding to a distance to the object, and, based on the light detecting position, outputs a long-range side signal that increases in value as the object is positioned farther from said camera at a certain intensity of the detected light, and a short range side signal that increases in value as the object is positioned closer to said camera at a certain intensity of the detected light; clamping means that compares the long-range side signal with a clamp signal, and, when the long-range side signal is larger than the clamp signal in value, outputs said long-range side signal and, when the long-range side signal is smaller than the clamp signal in value, outputs the clamp signal; calculation means that calculates a ratio between the short-range side signal and the signal output from said clamping means and outputs an output ratio signal; conversion means that compares the output ratio signal with a predetermined infinity determination threshold value to determine whether the value of the output ratio signal corresponds to a shorter range side rather than the value of the infinity determination threshold value and, if so, converts the output ratio signal into a distance signal that is correlated with the distance of the object from said camera, and, if not, converts the output ratio signal into a predetermined distance signal having a fixed value; luminance measuring means that measures the luminance of outside light; and exposure control means that, when the luminance of the outside light measured by said luminance measuring means is lower than a switchover luminance, which is determined based on film sensitivity, controls a lens aperture to a fully open aperture value, and, when the luminance of the outside light is higher than the switchover luminance, increases the lens aperture according to the luminance of the outside light, wherein the infinity determination threshold value is set at the value that corresponds to the shorter range side among a first auto-focus (AF) signal and a second AF signal, the first AF signal corresponds to the infinity determination distance that is set as the farthest distance measurable by said camera; and the second AF signal is determined based on the switchover luminance.