Abstract: A monocle can be provided with a light filter that transmits light wavelengths related to an animal's optical capabilities. The light filter will transmit light in the wavelengths and spectral sensitivity of the animal's retina rod photoreceptors, and in the wavelengths and spectral sensitivity of the animals retina cone photoreceptors during a specified light condition. The light filter selectively blocks certain wavelength ranges, such that the person using the monocle can effectively view objects in the same way as the animal does. The invention can be used to select clothing colors and patterns for camouflage purposes, select colored objects to be used in animal training, etc. A camera equipped with the desired light filter can also be used to aid in the selection process.