Orion-15 is available under 200 USD. As any old FSU RF lens it will need optics cleaning and lubrication of focusing part (two helicoids). Good part it is easy to do. No so good part, optical elements (four) mostly likely will be still not as good as new. I did it all within few hours. Lens is sharp enough in the middle on Leica M-E without shimming. Corners on mine Orion-15 are soft even at f16.
It is very small lens and fingers in the frame are big problem. I ordered ebay conical hood for wide lenses. Lens does fare and has vignetting.
Indoors it is easy to deal with. Aperture set to f8 (same as for outdoors), ISO400 and cheap, non-TTL flash, with shutter set on the flash symbol.
As you could see, above, I have my finger protruding in the frame. Canadian Thanksgiving Turkey was tasty.
Here is no flash indoor shot to test distortion.
As walkaround this lens is great after focus part was re-lubed. It is easy to zone focus by wire tie set on the end of the lens as focus tab.
On one meter.
For one hundred dollars more it is possible to get more advanced Canon 28mm f3.5 LTM lens. Which is legendary lens because it was used by Garry Winogrand. But surprisingly Orion-15 still has its fans. Time will show it I’ll become one of them. I like how inkjet color pigment prints come out for pictures taken with this lens.