This is similar to a problem posted a few months ago, but the cause seems to be different. So I am posting my issue here.
The problem was unique to my RF-S 18-150 mm kit lens, which relies on the MF/AF switch on the R7 body to set the focus mode. Basically, even when set to AF, I was getting stuck in MF mode if the manual focus ring was turned to "close focus" i.e. the AF square would disappear, the focus distance guide would appear, and the autofocus would be disabled until I manually “zoomed out” . Curiously, this was not a problem in A+ mode, which suggested a menu setting on my R7. Nor was it a problem with other RF lenses, including the RF 50/F1.8, which also lacks an MF/AF switch on the lens barrel.
In the earlier post, it was suggested that the issue could be remedied by toggling the “Lens Drive when AF Impossible” or the “Electronic full-time MF” menu options. Unfortunately, these did not remedy my issue; nor was it related to any other menu obviously referring to the manual focus ring.
However, after some trial-and-error experiments, I realized that I use back-button focus rather than the default front-button operation. As soon as I reset the function of the shutter button to both shutter and focus, the erratic behaviour disappeared, with all my other customizations left untouched. So it clearly seems to be an issue with how the manual focus ring on the RF-S 18-150 works when back-button focus is active. In any case, it doesn’t appear to be a hardware problem, and perhaps it will addressed in a future firmware update.
