[RioRico]

I'm guessing you wouldn't get the same result easily with a normal prime. The convex element to the rear of the Kiron is seriously curved!

Darn. Guess I'll have to paw through my glass and see what can be sacrificed that fits the criteria. I can get a similar, even exaggerated, effect with an impromptu 100mm setup. Ingredients:

* M42 bellows with PK adapter
* 42-49mm step-up ring
* 42-42mm thread-reversal ring
* cheap 49mm 10dpt closeup optic

With the closeup optic mounted normally on the bellows via the 42-49mm step ring, it's a 100/2.5 fixed-aperture lens with noticeable aberrations. Reverse it, and the edges go rather distorted. Just right for gooshy romantic portraits, eh?

[Hamster]

I have one in Nikon mount that is doing the same thing. I cleaned fugus out of the elements and un-stuck the shutter blades.

I suspected I might have reversed an element but I tried all combination and still working like that.

Perhaps the best to ask the question is Kiron Kid, he is on this forum and APUG.

Also mies in Kiron Made Vivitar but the internals are different from the one shown in Service manual.