LED banding is a major problem when using electronic shutters, and the Fuji X-T4 and X-T5 are no exception.
In the specific conditions of this piece, I found that setting the shutter speed below 1/100s tamed the problem. However, there is one major drawback: the number of ruined shots increases. This is particularly true of the moments when the actors are waving their limbs or moving randomly. In this case, the slower parts of the body remain in focus, while the peripheral parts do not.
Unfortunately, there is still no post-production technique that can eliminate this problem, which makes it difficult to achieve usable results.
Of course, using a mechanical shutter helps to reduce the possibility of LED banding. However, this option is not guaranteed to work all the time, and in professional situations such as classical music concerts or – as in this case – theatrical performances, there is no alternative to ultra-silent shooting.