Jupiter-12 Rear cap, contax mount.

[Hamster]

I have a black Jupiter-12 in Kiev mount, the problem with this lens is the bayonet mount seems to be loose, and sometimes I can even twist it off the camera, additionallly, the rear lens cap have the nasty habit of falling off all the time. I think it is an issue with the set screw not being adjusted properly.

Now I am not familiar with the Kiev outer bayonet, so I have no idea how to adjust them without damaging my lens.

Also for storage, I have my worries about using the supplied rear lens cap, I know it will just one day fall off when I am running with the lens in my backpack. I have taken to using a dead kiev body as a substitute rear lens cap.

Does anybody know off a cheap and effective way of substituting something for the rear lens cap? A dead kiev really is too heavy for the job.

 

[santino]

thats interesting, I got the same problems.

 

[VinceC]

Many common cans of spray paint in the U.S. use a plastic lid that includes a large outer cylinder and a smaller inner cylinder ... the small inner cylinder on many fits perfectly and snuggly on the long optical element of a Jupiter-12. This has been my standard cap for the lens for almost two decades. I used a pocket knife to cut away most of the plastic lid, leaving just the central plastic tube. I'm at work and the cap is at home. Will try to post a picture some time later.

 

[Bob L]

Here is what I did for one of my J12 that needed a rear len cap, just take a plastic 35 mm film container and cut off the open end so you wind up with a cap that is 13/16 long .
This gives you a nice tight fit on that big hunk of glass with plenty of protection, and there is no way it will fall off, been using one on mine for while and it work great.

 

[VinceC]

I just found out my plastic lid thinggy only works for an earlier 1960 chrome version of the lens. My 1987 black version uses a slightly skinnier housing for the rear element that makes the plastic lid too loose. I'll bet a cut-down film cannister would work. Seems like a near-perfect fit. And if it's a tad too loose, a layer of tape on the inside rim would probably make it snug.

 

[Hamster]

Your advise actually inspired me to go look for lid's at my workplace, there are some "sample" containers that looks like they will fit, kind of like containers for pond's cold cream. I think if I cut off the screw thread where the lid attaches, I can even get a "flange" that I can convert to a kiev bayonet mount!

 

[Eugen Mezei]

The big back element of this lens is painted black on the peripherial. Would a cap tightly fitted aorund this element not rub the black paint away?