Conclusion from LensRentals:
This is not marketing department weather resistance. This is engineering department weather resistance. Anything that can be sealed has been sealed. I’m impressed, and I will say for future cut-and-paste blurbs: this is as robustly weather sealed a camera as we’ve ever disassembled.
I don’t believe in weather resistance myself. I believe like life; water will find a way. I believe in plastic baggies and rubber bands. I am, however, a great believer in the idea that if you claim to do something, then damn well do it right. This is done right.
I’m impressed by the very solid construction of the chassis and IBIS unit. I’m impressed with the neat, modern engineering of the electrical connections. Yes, I’m aware that soldered wires carry electricity just fine, but to me, there’s something reassuring about seeing neat, well thought out, 2018 level engineering.
I’m not here to tell you which camera is best to use or has the best performance. I’m just here to say this is a damn well-built camera, the best built mirrorless full-frame camera we’ve taken apart. (For the record, I haven’t torn down a Leica SL.)