Hi Pete, I have found Tony Phillips 720 page digital book to be invaluable. Besides explaining all the details about the camera, he includes lots of basic photography guidance that applies to any camera. Well worth it! Here is a link... https://tonyphillips.org/product/xh2/?v=fdd13832cd81.
Hi, sorry for the late reply. Yes, as far as I know it's better to have the camera switched on to lock the sensor in place. I've been using this method since I bought an X-T4 a few years ago with no problems. It seems to be the recommended practice. If you do a search on YouTube you'll find some more in-depth videos on the subject.
My go to 56 f/1.2 early version lens aperture ring feels stuck but will free up with moderate twisting force then works relative easy but when mounting to my X-Pro2, the lens stops down to aperture set at the time making composing my shot difficult - manual focusing impossible. I bought this lens new and has produces many gorgeous imagines. It still does though as I said with the viewfinder "dark" composing is hit and miss. The "fat" size of the lens allows aperture ring to make contact with surface where camera/lens combo is placed though both have been gently used. Sometimes I think the aperture ring is slightly bent because of this. Any ideas?? This lens is so awesome I can't imagine the new version being a significant improvement optically and I have no plans to upgrade. This and the 23mm f1.4 are both awesome a complete my Fuji kit.