I found this picture on the web, posted by a fellow I know in the motorspots industry. The picture was taken 30 years ago, in 1980 by Rich Chenet. Rich used a mirror lens. I don't know the focal length, but it's got to be 300mm or greater, based on the nature of the shot and the track he's shooting (Pocono). Mirror lenses tended to bokeh in interesting ways.
Credit Rich Chenet for the picture, and Larry Lawrence for making it available to me.



