Auto Extension Tube Set - Nikon
Extension tubes are designed to enable a lens to focus closer than its normal set minimum focusing distance. Getting closer has the effect of magnifying your subject (making it appear larger in the viewfinder and in your pictures). 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.
These Auto Focus extension tubes are designed with all the circuitry and mechanical coupling to maintain auto focus and TTL auto exposure with most lenses given there is enough light to activate the cameras AF system properly.
The set contains three tubes of different length, a 12mm, 20mm, and 36mm, which can be used individually or in any combination to obtain the desired magnification. these extension tubes have metal bayonet rings.
PLEASE NOTE THE FOLLOWING: The focus range will be greatly limited to a very close focusing distance. There is light fall off when using any extension tube, sometimes the equivalent of 3 f-stops of light is lost when using multiple extension tubes together. This light lost can affect the camera's ability to auto focus. Manual focusing is recommended should the lens begin to "hunt" (not lock onto the subject).
AF Auto Extension Tubes from Premier Ink & Photographic