Optical instruments are normally classified into: projection instruments and observation instruments. What is the difference between them?
Projection Instruments – are instruments that are characterized by forming a real image that can be projected onto a screen, such as a screen. Examples of projection instruments are: the camera and projectors.
• Photo camera – this is a device that is used a lot by people. A photographic camera is basically formed by a camera obscura that contains a lens, called an objective, and the film, where the images will be projected. In a general and simplified way, the image projection process on film occurs as follows: the camera objective, which is a convergent system formed by one or more lenses, it projects the real and inverted image onto the film, on which the image will be recorded over the action of phenomena photochemicals.
• Projectors – these are devices that project an image of a real object onto a screen that can be viewed by multiple viewers. They consist of a converging lens, the objective, which provides the real, inverted and larger image of the object. In its constitution there is also a concave mirror that is placed behind the projector lamp and is used to better illuminate the object and minimize the loss of light energy.
Observation Instruments – are instruments that provide a virtual image of the object, we can mention: the magnifying glass, the telescope, the telescope, and the microscope, for example.
• Magnifying glass – Also known as a magnifying glass, it is a simple lens that provides the virtual image, straight and larger than the subject.
• Compound Microscope – is a device used for observing very small objects. It is made up of two converging lenses, usually composed. The first lens is close to the object, the objective, and the second is a magnifying glass called eye, it is with this that we observe the image provided by the objective.
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By Marco Aurélio da Silva
Brazil School Team
Optics - Physics - Brazil School
Would you like to reference this text in a school or academic work? Look:
SANTOS, Marco Aurélio da Silva. "Projection and observation instruments"; Brazil School. Available in: https://brasilescola.uol.com.br/fisica/instrumentos-projecao-observacao.htm. Accessed on June 28, 2021.
