The ocular lens and the objective lens are both crucial components of a microscope, but they serve different purposes.
The ocular lens, also known as the eyepiece, is the lens that you look through at the top of the microscope. It typically has a magnification of 10x or 15x and provides the final magnification of the specimen being observed. The ocular lens brings the image into focus for your eyes and can also have additional features, such as a reticle for measurements.
On the other hand, the objective lens is located near the specimen being examined. Microscopes often come with several objective lenses of varying magnifications (e.g., 4x, 10x, 40x, and 100x). These lenses gather light from the specimen and magnify the image before it travels to the ocular lens. The objective lenses are responsible for the majority of the magnification and detail in the image.
In summary, the ocular lens is what you look through and does the final magnification, while the objective lens is positioned close to the specimen and provides the initial magnification. Both lenses work together to allow you to clearly see and analyze the details of the specimen under the microscope.