An image obtaining method of an image obtaining apparatus including a filter that reduces light of a first wavelength, the light being used for adjusting a focus, according to an embodiment of the present invention, may comprise the steps of: selecting a filter corresponding to a brightness of a photographing region from among one or more filters, wherein the one or more filters include a second filter that reduces the light of the first wavelength; adjusting a focus on the basis of light obtained from the photographing region on which the light of the first wavelength is irradiated; and obtaining an image by using light obtained from the photographing region through the filter corresponding to the brightness.