Remove old fungus in Carl Zeiss Jena Sonnar 1:2 f=5cm for Contax 

Hello Erwin, I don't know about the Ammonia Hydroxide because I have not try to use it yet, but I have used Hydrogen Peroxide 3% to remove Fungus in many, many lenses and I get always surpriced how good it works without damage the lens element coating. When cleaning a lens with Hydrogen Peroxide 3% on a good quality lens wipe, you will ONLY need a very light pressure, to remove more or less of the Fungus and sometimes you will need to do a second time to get the rest of the Fungus off. This is just my own experience, but I hope it can help you and other people

@@mikeno62 Hello . I will try your hydrogen peroxide 3% . I have seen about ammonium hydroxide (sorry , ammonia hydroxide was the wrong term) on the channel : " retro foto house" , episode : "helios 44-2 fungus cleaning tutorial" , and i am surprised how the person uses this , because when i open my bottle of ammonia 25% that i bought , which is the same as ammonium hydroxide (ammonia diluted with water) , then i can almost not breathe from the fumes coming out . I learn from your video's . If ever you find a Soviet Kaleinar-3 lens 150mm , then i would appreciate the video . They are very big and much fun to do . Regards , Erwin .

Oh... one more question. I see there is no focusing ring on this lens. So is that focusing mechanism an integrated part of the camera body? And this may make it not suitable for adaption to mirrorless? Or am I wrong and there is a solution.

@@samsen3965 Kipon makes contax RF to fuji X and sony E adapters, but those are nearly 400 USD. The other way I know of is contax RF to Leica M, and then Leica M to whatever mount you need. I'll probably stick a helicoid to a body cap and fit the lens to the helicoid myself, but if I could afford one of those Kipon adapters I'd definitely go that route. Those are gorgeous.

I would guess it should be possible, but I have not try that yet, but I will try it with an old lens sooner and make a video about it.

@@mikeno62in any case, even after removed damaged cement, watching this ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-oWtgGuPyDwA.html is clear that re-cementing is not possible without required equipment

@@antares2112L you can make your own tools for that, actually. Just set a laser on top pointing straight down and the lens itself on some ball bearings, then be careful to set everything so that the laser points exactly through the middle of the ball bearings hole. Easier said than done, but it can in fact be done

@@JeffDvrx it sounds tricky, is there any video of such a feat?

I would guess its the way they make the micro adjustment of the lens, so the focus is correct.