The objective on a microscope is comprised of a tube and one or more lenses, and may include a mirror as well. Its purpose is to gather and focus light, typically while magnifying the image, from the sample or object under study. Objective lens on a microscope collects the light emerging from the sample and focuses it into the objective turret. Its primary role is to increase the magnification used for viewing.usually, there are three or four objective lenses on a microscope.
Most microscopes have four objective lenses, and each provides a varying level of magnification. The shortest objective possesses the least power (4X), and is called the scanning objective. It is followed by the low power objective (10X) and the high power objective or “high-dry” objective (40X). The longest objective, which is also the strongest, is the oil immersion objective (100X). The maximum magnification potential of an objective lense is typically determined by its distance from the image plane and the specimen that’s being observed.The objective lens is the image-forming lens in a microscope system. Illuminating radiation interacts with the sample and then passes into the objective lens which forms an image. This image is then projected onto a detector, which could be your retina, photographic film, or a digital camera sensor.The objective takes the radiation that has interacted with the sample and focuses it into an image. In some types of microscope systems – scanning optical microscope systems – the objective lens focuses the illumination to a small point, which localizes the radiation so that it can be rastered across the sample. This point interaction with the sample is detected, and forms an image in which this interaction is detected serially point-by-point.
Formally, it is the optical element that handles the largest angle rays in the optical system, and therefore must have the most uniform focusing quality across its field of collection. For this reason, the objective is typically the most important optical element in a microscope system, as it defines the resolving power of the microscope and its construction has the greatest effect on the quality of the image that is formed.
