Zeiss glasses are great optics. Sometimes I want to buy some again and file down focus tit to instal normal focus tab.
But aperture ring is too harsh. Moder Leica aperture ring is made to be operated by one finger, because another is on the focus tab.
Zeiss aperture ring made for truck drivers. If you get used to grab driving wheel and hold it very firm, then Zeiss is your lens.
If you google Zeiss wobble it should find one forum thread where known in USA repair person explains why. He blames Zeiss on choice of wrong materials which worn out.
My rangefinder.ru buddy had Zeiss ZM as I have lenses, in a lot of use. He has to give to fix Zeiss wobble three times.
Wobble depends how lens is used. I'm not gear collector and rare in lens use. I have usually one, two lenses I use every day, if I like them. I'm on my third most used lens now and it is not Cosina made. No wobble so far.
Cosina made some lenses will develop wobble. I have two 35 viogt as every day lens. First has wobble and focus tab loose.
Second within more shorter period - wobble.
I must say, both of us are street, reportage photogs, and we are using focus tab for fast zone focusing. I guess, if you rotate focus ring slow it should last without parts unscrewing longer.
Most of them, if DIY, could be fixed by this lock lite, BUT, not red! Red is for permanent! Blue works, but only very small amount should be applied. I "lubricated" my Jupiter-3 lens block with blue lock lite and now it is non removable from focus part.
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