The Extension Tube EF 25 is installed between the prime lens and the camera body. It is a simple way to enable close-ups at high magnifications by increasing the distance between the lens and the film plane enabling focusing at closer distances than otherwise possible. This close-up accessory maintains full electronic coupling between the camera body and lens and can be used with most EF lenses. Ideal for nature photography with single focal length telephotos. Manual focusing is recommended.