1. An auxiliary light projection system employed by a camera having an auto-focus detection unit, comprising: a light pattern generator configured to generate an auto-focus detection pattern, the auto-focus detection pattern comprising a first pattern region and a second pattern region that is denser than the first pattern region, and a center of the first pattern region and a center of the second pattern region are separated by a distance determined in response to difference in visual characteristics of the auto-focus detection pattern between when viewed (i) from an axis through the lens of a camera and (ii) from an axis through a focus pattern projection source; and a light pattern projection source configured to project the generated auto-focus detection pattern onto a subject enabling auto-focus detection.