Focal Reducers have been around for many years for telescopes, but now I see they're becoming extremely popular for adapting full frame, even medium format lenses to e.g. M4/3 cameras. Other combinations as well, but my interest is in the M4/3 option.
More specifically, it seems that they could be an excellent tool for increasing the light gathering power of a lens for astrophotography ( I might abbreviate that to AP, its a long, slow word to type, especially with just two fingers).
Searching eBay gives a quite bewildering array of options, and prices. Searching Google also gives a wide range of opinions, but not much in specific details such as sharpness, distortion etc.
So, does anyone on this forum have any experience, information, opinions which would be applicable to AP ?
Twin E-620/70-300mm/14-42mm/pinhole lens, plus 8mm FE, Tokina AT-X 90mm macro, and Zeiss 500/8 mirror.