Crew normally couldn't care less. You're more likely to encounter a paranoid/busybody fellow passenger who thinks it's "illegal" or dam' well ought to be
.
Just explain calmly and politely that there in fact is no law prohibiting what you are doing. If they still then go bleating to the FA or (even worse) a FAM, it's probably best to put the camera away just to avoid GBH of the earholes. There'll be other days.