Mysterious notch on Jupiter 12

[GeorgeFH]

I have this Jupiter 12 that has a mysterious little notch on its lever. Looks like someone machined a corner of it. The lens doesn't lock on the camera body, but performs fine. Anyone know why someone would do that?
BTW, what's the purpose of that little lever anyway?

pics attached

thanks
George

 

[wyk_penguin]

You mean the one that you're pressing on?

 

[varjag]

The lever is to lock the lens on the outer bayonet of Kiev.

The notch is supposed to be there. If your lens doesn't engage with the bayonet, it means either the bayonet was poorly machined, or the lens mount collar was set not precisely enough. The latter you can tweak by loosening the set screws on the collar; the former means you have to file away some of the outer bayonet where it engages with the lock.

 

[GeorgeFH]

thanks 🙂 stupid me. now, what do you mean by "lens mount collar"?