A high power objective lens is an important part of a microscope that magnifies up to 40 times. This lens is used for observing fine details such as muscle striations and retinal nerve cells. The strength is second only to an oil immersion objective lens, which magnifies up to 100 times.
A microscope can have up to four different types of objective lenses. The eyepiece lens is a 10 times magnification, or 10X. When coupled with the four different objective lenses, the maximum magnification of a microscope can be 1,000X.
The smallest lens is the scanning objective lens. It measures at 4X, and it is the shortest lens of the four. It gives the observer an overview of the entire slide. The next size up is the low power objective lens at 10X. It is the lens used most often, as it is useful in viewing many different types of slides.
The high power objective lens comes in a bit higher than the low power, and it is the first one on the scale that is retractable. A retractable lens is one that is spring-loaded, which means that if the end of the lens touches the slide, the end of the lens pushes up. This protects the slide from cracking and potentially ruining the specimen. It also protects the lens itself from cracking or becoming scratched. Some microscopes have an oil immersion lens, which is a step up from the high power objective lens. This lens has to be used with a special oil to aid in viewing the specimens.