DescriptionThis is used by attaching between canera body and lens of the 35mm single-lens reflex camera,it comes as a set of 3 tubes of different lengths which singly or in combination makes it useable in 7 different lengths,it couples perfectly with the camera's automatic diaphragm,with cameras of TTL,AE (Through-the lens,Automatic,Exposure)type it gives perfect coupling expect when combined with electronic flash AE unit.the imagic magnification ratio becomes smaller as the focal length of master lens becomes longer and the larger as the focal length becomes shorter .also,the distance to the subject becomes further away as the focal length of master lens becomes longer and closer when it becomes shorter.In close-up shooting,as the subject's depth of field becomes shallow,never forget to stop down the lens.take care that when image magnification ratio increases camera shake is also liable to increase.(the use of tripod and cable release is advisable.) Its dim ensines are: Tube diameter:ab.62mm Tube lengths:12mm+20mm+36mm Package 1*12mm+20mm+36mm 1*Manual 1*Silica gel