Note that producers whose only presence in the photo industry at any time has been the manufacture of digital cameras (Logitech, for example, which has made Webcams) are listed separately on the List of digital camera brands.
Some camera manufacturers sell lenses made by others as their own, in an OEM arrangement.
Note that many optical instruments such as microscopes, telescopes, spotting scopes and so forth can be used as photographic lenses; manufacturers of these types of equipment are not included here (unless they also make more conventional photo gear).
Note films, paper and chemicals may be sold by a manufacturer who has produced the product under their own brand or alternatively under a brand name owned by one party, with manufacture and packaging of the product outsourced to third parties as well as many permutations of these options.
Therefore, this list includes both brands and manufacturers with information (where known) on their current capability.