Image pickup apparatus, setting apparatus, wavelength acquiring apparatus, and storage medium

A wavelength acquiring method for an image pickup apparatus that includes an image sensor configured to photoelectrically convert an object image formed by an image pickup optical system including a zoom lens and a focus lens, the wavelength acquiring method comprising the steps of:

• preparing focus data indicating an in-focus position of the focus lens according to an object distance and a position of the zoom lens;
• and
• acquiring a wavelength of imaging light incident on the image sensor,
• wherein the focus data includes data for visible light and data according to a wavelength of infrared light,
• wherein the acquiring step acquires the wavelength of the imaging light using the focus data, the object distance, the position of the zoom lens, and a position of the focus lens when the image pickup optical system is in focus in a state where the visible light and the infrared light can enter the image sensor,
• wherein where a data in-focus position represents the in-focus position of the focus lens in the focus data, and an actual in-focus position represents the position of the focus lens in the image pickup optical system that is in focus, the acquiring step acquires, as the wavelength of the imaging light, a wavelength that corresponds to one of the focus data in which the data in-focus position for the object distance and the position of the zoom lens when the image pickup optical system is in focus coincides with the actual in-focus position, and
• wherein there is no focus data in which the data in-focus position for the object distance and the position of the zoom lens when the image pickup optical system is in focus coincides with the actual in-focus position, the acquiring step acquires, as the wavelength of the imaging light, a wavelength of one of the focus data in which the data in-focus position is the closest to the actual in-focus position or a wavelength obtained by an interpolation using at least one of the focus data in which the data in-focus position is close to the actual in-focus position.