Kenko Auto Ext Tube Set for Nikon LensesPerfect for Macro Photography Effect. Never Used, kept stored in our Safe for 2 years, Retails for R3500 minimum.The Kenko Auto Extension Tube Set DG contains three tubes of different length – 12mm, 20mm, and 36mm – which can be used individually or in any combination to obtain the desired magnification. Actual magnification effect changes with each specific lens. They are exceptionally useful for macro photography, enabling you to convert almost any lens into a macro lens at a fraction of the cost while maintaining its original optical quality.to maintain auto focus and TTL auto exposure with most Nikon lenses given there is enough light (at f/5.6 or brighter) to activate the cameras AF system properly.