Fotodiox Pro Auto Macro Extension Tube for Hasselblad XCD Mount Mirrorless Digital Cameras are automatic tubes that communicate all electronic functions from the lens to camera, including auto-focus and auto-exposure. Macro extension tubes are a wonderful alternative to expensive macro lenses. Macro extension tubes maintain the original optical quality while transforming the normal lens into a macro lens. By placing distance between your camera body and lens, focusing distance is shortened and the effect of magnifying your subject is created. Because no optical components are added into this extension tube, the image preserves the original optical properties of the lens. This is far more desired than the close-up lenses which are added to the front of the lens via filter thread, which alter the optical quality resulting in a blurry image full of artifacts. Adding an extension tube increases the effective aperture, reducing the amount of light entering the camera, which means you will need to use either a longer shutter speed or higher ISO to compensate for the loss of light. Your camera, if it's set to an automatic exposure mode, will take care of this automatically for you. Macro extension tubes are an affordable and simple way to turn any existing lens into a macro lens.