This question raised the issue of on-topic vs off-topic in comments.
The end use of the photograph is for engineering purposes. There is no mention in the site guidelines about whether scientific, engineering, or technical photography is photography. Of course, there is no true answer, it is just a decision of the site what people they want in the community.
It seems one line in the on-topic or off-topic in the guidelines resolves the uncertainty. My meta question is just that:
How do site guidelines evolve?
I'm not asking specifically about the disposition of this question, nor advocating one side. My interest is more general:
Do people prefer to leave the guidelines loose and let each question fly on its on merit? This has the advantage of flexibility, but also can discourage new users who's question gets shot down.
Should the guidelines be more specific so that people know what to expect? While a big rule list might be certain, that also could look unappealing as being micro-managing or overly dictacting.