Pipes can get all sorts of messy but guessing wrong can create more problems than the plumber started with. Pipes have a lot of potential problems, from leaks to obstructions, and plumbers have developed a lot of different ways in order to deal with them. Obviously a good inspection is a good place to start, and smaller pipes can be torn apart to determine what the problem is but for longer pipes, especially for those that are mostly hidden from view, something a little different is needed.
The pipe inspection camera comes in a variety of shapes and materials, as well as different levels of stiffness, all in order to deal with a variety of different pipes and potential problems. Most inspection cameras are either metal or rubber, but a number come in plastic. The difference in materials is in order to deal with different potential obstructions and lengths of pipe; in general, metal is used for shorter lengths with more solid obstructions while rubber is used for longer pipes with fewer obstructions. The metal allows a plumber to push through stiffer gunk, while rubber allows for a better extension. Plastic is sometimes used, but usually for smaller pipes.
Each one of those can be broken down to different levels of stiffness. Home plumbers prefer a really stiff camera as it is better to push through the usual gunk that may be found in a household pipe;with a little luck the camera can be used like a snake and provide a start on removing the problem material. On the other hand a more flexible camera can be extended over a greater distance and deal with a number of different issues with just a little fine manipulation. Between the two a wide variety of pipes of varying lengths can be dealt with, especially if the plumber has some experience dealing with them.
While there is not a lot of variety in terms of actual shape, the difference is mostly in the head. The issue is that an inspection camera needs to be as streamlined as possible; different shapes just do not lend themselves to a lot of different uses. However, the head of the camera is allowed some differentiator depending if it has to be used to poke through gunk or be wound into a pipe. Some cameras are level across the top to make it easier to push them through while other sometimes have little wheels attached to the camera in order to make it easier for them to go through the pipes.
There are of course other levels of specialization. Some cameras have night vision capabilities while others have lights. While there really is not all that much of a difference between different inspection cameras, those differences can mean the world to the plumber using them. It should be noted that non-plumbers use these cameras as well, especially electronics specialists and even spelunkers, so they see a lot of use. As they can be used in a number of different way, they are always a popular item.