A microscope may be a combination of :

A compound microscope is typically a combination of two convex lenses: the objective lens and the eyepiece (ocular lens).

• Objective Lens: Placed close to the object being observed, it has a short focal length and forms a real, inverted, and magnified intermediate image of the specimen.
• Eyepiece: Positioned near the observer's eye, it acts as a simple magnifier. It takes the intermediate image formed by the objective lens and magnifies it further to produce a final virtual, inverted, and highly enlarged image.

While a simple microscope uses only one convex lens, the dual convex lens system in a compound microscope allows for much higher magnification and resolution, making it essential for biological and scientific research.