Patent ID: 8823867

Claim:
A camera having an image sensor for forming a subject image via a photographing lens, comprising: a contrast detection section for detecting a contrast value based on image data acquired from the image sensor; an assist light section for irradiating a subject by emitting light at a first luminance amount or a second luminance amount that is dimmer than the first luminance amount; and a control section moving the photographing lens and detecting a focus position of the photographing lens based on contrast values detected by the contrast detection section at different positions of the photographing lens, wherein the control section causes the assist light section to emit assist light in a first luminance amount or a second luminance amount when acquiring arbitrary image data from the image sensor, and detects a focus position of the photographing lens based on one of a first contrast value that is detected by the contrast detection section in a state where the assist light section emits light in the first luminance amount according to a position of the photographing lens, or a second contrast value that is detected by the contrast detection section in a state where the assist light section emits light in the second luminance amount according to a position of the photographing lens, and wherein the control section changes a position of the photographing lens over time, and detects the first contrast value and the second contrast value using the contrast detection section by causing the assist light section to alternately fire at the first luminance amount and the second luminance amount in accordance with the position of the photographing lens.