I’m writing a mystery novel about someone sending photos, and one main clue is that they have a niche for photography. Does that even exist? Like, the two main characters would analyze their angles, lenses, and such, then be able to look at the mysterious senders photos and try to figure out who was sending the pictures. Do photographers really have niches?
Many are general photographers they take photos of anything and everything, those that specialist have niches like portrait, product, architecture and more.
What you are asking about is not niches its style (analyze their angles, lenses, and such, then be able to look at the mysterious senders photos and try to figure out who was sending the pictures), the better a photographer gets the more refined their style becomes.
I don’t think you idea is viable or convincing, there are millions of photographers out there, unless they are excellent picking whose photos are whose from random photos is difficult to impossible.
I’d call it a signature more than a niche. Everyone falls into habits and pictures start to get identifiable. A niche would be more like his place in the industry of craft. “He found his niche in the fashion industry” for instance.