To me the 21mm Super Angulon is a special kind of lens. Mine has produced some of my best images. The only magazine cover I ever sold was a 21 SA shot. Another time while traveling in India was able to get access to the crypt beneath the Taj Mahal. Just time for one frame wide open on Kodachrome 64. Was loaded for bright sunlight and never expected to get a chance for such a shot.
Occasionally while shooting contra jour, I've had an unusual type of flare show up. It looks like bars of a rainbow and in some cases can be quite attractive. Have tried to reproduce the effect but it happens very rarely.
I don't have much luck posting images on RFF so will just provide links in case anyone has an interest. All were shot with 21mm Super Angulon (Later f/3.4 version) on an M4.
Beneath the Taj..
Hanging out with the hippies in circa 1970 Kathmandu..
A weird flare shot.
I bought my 21 new in 1970 for the grand sum of $363 and think that included finder. What a deal! :-) It's a lens I'll never sell.