Orion Focal Reducer, 0.8x for ED RefractorsReduces an astrophotography refractor's effective focal length by a factor of 0. 8x, providing a shorter, more optically fast focal ratio Now includes interchangeable male M42 and M48 "wide" thread on camera adapters (T ring for your camera sold separately) Also flattens the field for sharper stars at the edge of the frame Enables a refractor to both acquire a larger field of view and to capture bright, detailed astrophotos in considerably less time