Cameraman or camera operator are for those that use cameras, but what would a business card of someone who makes cameras for a living say? "Camera maker" is the closest to accurate, but somehow feels wrong. "Optical engineer" gets thrown around a lot for the lens maker, but not for the camera as a whole.
There is no single word for this.
Here, Wikipedia calls them photographic equipment makers. For subcategories, it uses terms like camera and lens manufacturers and camera accessory makers. At one point, the article refers to camera makers as producers of cameras. In this article about the history of the camera, Wikipedia also calls them camera makers.
Here, a webpage devoted solely to the love of cameras (and thus an uber-reliable source) calls them camera makers as well. They also use the term distributors as well as the term camera-related companies.
Many other sites I visited also have nothing better to call them but camera makers. This search on a reverse dictionary yielded no results for a single word concerning "camera maker" or "manufacturer".
It is clear that one word is impossible, unless you make it up, of course. The next best thing to do is to say the most prevalent term, so as to maximize comprehension and have that smug satisfaction that you are using the correct term. It was by that logic that I ran a search culminating in this Ngram that found camera maker to be about four times more prevalent than the runner-up.
It's entirely your choice, of course, but I vote for camera maker. It is, after all, self-explanatory.