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The Camera Lens

September 11th, 2007 · No Comments

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It is the job of the lens to get the light into the camera and onto the medium so it can be recorded as an image. A lens has many ways of modifying light and can be used to adjust the brightness, focus and magnification of the image in various ways. The following table lists common lens functions, what they do and how they are measured:

Name Function Measurement Factoid
Zoom Allows you to get closer or further away from your subject without having to change your physical placement. Measured in millimeters (mm). Lenses that can not zoom are known as “prime” lenses.
Focus Allows you to create sharp areas and soft/blurry areas of an image based on the distance from the camera. Measured as a range (in feet or meters) from the camera. The focus range is also affected by the zoom and aperture settings.
Aperture Literally the size of the opening that the light travels through to get to the medium. Controls how much light enters the camera. Measured in numerical values, often called f-stops (f2.8, f4.0, etc…). It might sound backwards, but the smaller the numerical value of the aperture, the larger the opening and the more light that enters the camera.

Most cameras have an option to manually control some or all of these functions. On SLR cameras, the functions are usually controlled by moving physical elements of the lens itself. The majority of compact cameras also offer control of these functions through use of dials, buttons or a menu system.

Be sure to read all the articles in this series

 

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Tags: Your Camera 101, The Basics

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