M42 Macro Focusing Helicoid Tube Adapter
The macro function of this adapter provides a focusing helicoid that will increase the lens-to-sensor distance, allowing for closer focusing than normally allowed by the lens itself. The greater the length of the extension tube, the closer the lens can focus. This means you can now get macro performance without needing to switch to a specialized lens and you will retain all the normal benefits of your optic when the macro function is not in use. This macro helicoid can be used with any M42 adapter on either end: allowing you to use M39, M42, Nikon, Leica and more lenses on any M42 camera body, or an M42/M39 (with adapter) lens on Nikon, Canon, Sony, Olympus, and more camera bodies. This helicoid tube is also very useful for lenses without a focus ring such as enlarger lenses.
The all metal design and polished coated surface is designed to guarantee smooth mounting and long lasting experience. Although the lens will fit physically, automatic diaphragm, auto-focusing, or any other functions will not operate correctly while using this adapter. In this case 'stop-down mode' will need to be used when metering since the lens does not have the ability to have its aperture controlled by the camera body. You can shoot with manual mode or aperture priority mode.