This has come up before, but mostly in the context of video (see What is meant by "photographic equipment" as reference in the help center?), although it's also a frequent issue around industrial/scientific optics and computer vision (see Are questions about industrial optics on topic?).
Basically, over the years, we've come to the general consensus that we want this Photography site to be focused on questions that pertain specifically to the art and science of photography, not necessarily every possible thing you can do with a camera. (Just as a question about using a hammer to crush eggs would be off topic on a carpentry site, even though it's about "carpentry equipment").
I think this is a good thing, and I think it's good that we close questions that don't fit; that helps keep the signal-to-noise ratio high, and should encourage more questions about photography and photographs and keep the site from being overwhelmed by these other uses. And, judging by the reliably-fast closing of such questions, I think most active users here agree. (Also see Is there any hope for making this site about photography? and Why are printers, earplugs, and shoes on topic, but not video, graphic editing, or computer vision?)
But, the help center still has ""using photographic equipment" in the on-topic list. This is a request to qualify that with "(in the context of photography)".
The current disconnect between the help and site practice leads to frustration like How would one digitize a thick book into a PDF version in the most time-efficient way, using only a camera and a computer? — clarifying would help.