I am trying not to insult People by asking super dumb and Basic Questions, but sadly more often than not i seen the Problem actually being the most Obvious and Basic Errors, so i kind of have to ask at some point. However, thanks a lot for Clarificaton, so i can assume you know the basics on how to handle and Mount Optics and such.
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As for QC, i had my hands on Adapters from this type from three different Batches, and Krontech had quite some QC issues on the First run, was really not happy with that one and sent it back myself. the Next batch was better, but still had some Flaws, however i did Keep that one, and just fixed the Problems myself, as i just needed a Mount eventually, and sending it back and fourth gets expensive.
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as for the part if its a QC error, i have to ask, do you have access to a Micrometer somewhere (decent Quality digital Calipers would also work, but its a lot more difficult to meassure with)? If so, i might give you some instruction on how to meassure if its in Specification on size (i have a guess on what the Issue probably is).
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From my own testing and Reverse-Engineering of the MFT-Specification itself, there is Quite some Tolerances involved in MFT Lenses and Adapters, and Metabones Speedboosters being on the Tighter Side. So if you have any very Cheap Native MFT Mount Lenses or some of the Cheap China MFT Adapters, try to mount one of those and see, if that will mount propperly.
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Krontech Customer Service in General is good, but it can be a bit of a Pain and take some time to even get some Conversation with them going. But once you manage to get a Conversation with someone from Krontech going, it usually goes pretty smooth from there (at least it did for me whenever i needed anything so far).