This is macro focusing adapter, extension of helicoid is about 26mm to 56mm.
Also, it is very well made (of brass and aluminum) adapter, which will allow you to use Carl Zeiss, Pentax or other brands M42 (42mm x 1.0) screw mount lenses on Sony E mount APS-C camera. (For full frame E mount camera, cropping image is needed.)
Best fit for macro photography, also support focusing infinity at closure.
You can also use an M39-M42 adapter ring (also available in our store) to fit M39 lenses with this adapter.
- Put red marks of the adapter and lens collar together.
- Turn the adapter clockwise till the fixative click.
- mosty it will use Manual or Av mode.
To remove the adapter you should unpress fixative pin and turn the adapter anticlockwise.