Having the appearance of a telephoto lens, the attachment with built - in mirror attaches to camera lens for taking candid shots. For shooting "true to life " pictures, it allows to take discreet right angle shots without subjects's knowledge, in particular where it is absolutely impossible to aim the camera towards the subject. As the camera is not aimed at the subject, It helps to capture the subjects natural mood and spirit and completely eliminates camera concious reactions like feeling of shyness, not desiring to be photographed, or a completely unnatural expression. To avoid vignetting,Its use is restricted with telephoto lenses of 70 mm focal length and above. This Right angle scope fits lens with filter thread size 58mm