While most common microscopes, especially those used for biological applications, rely on objective lenses to magnify the specimen, there are other types that don't.

Here are examples:

* Scanning Electron Microscopes (SEMs): These microscopes use a focused beam of electrons to scan the surface of a sample and create a 3D image. They don't use conventional objective lenses in the same way light microscopes do.

* Scanning Tunneling Microscopes (STMs): These microscopes use a sharp tip to scan a surface and create an image based on the flow of electrons between the tip and the surface. They don't use objective lenses either.

* Some Simple Microscopes: Very basic microscopes designed for educational purposes or hobbyists might not have objective lenses. They might use a single magnifying lens instead.

So, while objective lenses are a crucial component in most microscopes, their absence is not necessarily a defining characteristic of all microscopes.