The focusing capability of the attachment lenses is expressed in diopters, the higher the value, the greater the focusing ability. What reproduction scale can we get with a lens? The greater, the greater its focusing ability and the greater the focal length of the lens used. At 100 mm focal length and +4 diopter lens we get a scale of 1: 2.5 - this is enough for photographing flowers or butterflies. The object distance is about 25cm. The use of a 200mm lens in combination with this lens gives a scale of 1: 1.25, with practically the same object distance.