Here it is, I could process a color slide film using my new heliar 15 and Jupiter 8.
I love the 15mm though it can not be used for every purpose. The silly thing is that I made fall the viewfinder last week (stupid me, I had it since less than 1 week). Then I'll soon buy another viewfinder (there's no lock feature on the viewfinder, so it's better to remove it from the camera body when not using it).
Here are a few 15mm test shots :
and one with the Jupiter 8 + vivitar 283 flash :
Though these are not outstanding pics, I'm happy of this buying !