Nahum D. Solomon Pr. Tim Johnson November 30, 2009 Wentworth Institute of Technology

 Light is bent when it passes between substances having different densities  The camera lens bends light in a precise manner, redirecting rays to converge at a point

 Lens focal length is defined by the distance between lens and focused image on sensor of a subject at infinity. Focal length is often referred to as “angle of view” by photographers

 On digital cameras, focal length is often expressed as 35mm film camera equivalent  Higher focal length number indicates a greater image magnification › Telephoto ~ mm › Normal ~50mm (human eye) › Wide angle ~18-35mm

 Angle of view / magnification trade-off  Zooming out” uses shorter focal length, providing wide- angle view  “Zooming in” uses longer focal length, narrowing field of view so objects appear large

 Collection of photos taken from same position with lenses ranging from wide angle to telephoto: 24mm, 35mm, 50mm, 100mm, 200mm, 300mm

 A cross-section of a camera lens shows it is constructed of a complex series of multiple lenses  The array of concave and convex lens elements is designed to correct for optical aberrations

 Zooming in allows filling the frame from a distance  Keeping at a distance allows candid shots  Short depth-of-field nicely blurs background

 Wide angle lens may introduce perspective distortion Might make pictures appear feather or longer than they really are Allusions

 Wide-angle close-ups distort facial features, giving a "fish bowl" effect Can make you look weird or scary

 Use to capture a large area picture › Used in a crowd › Used to capture a wide building/area

 When you buy a camera, BUY THE LENSE THAT MATHCES THE BODY!!!!  The auto focus system adjusts the focus to make the subject in the center of the viewfinder appear critically sharp.  Auto focus may have trouble focusing in certain situations › THEN USE MANUAL ZOOM

At times more expensive then the Body of the camera Range from 90$-500 Depending on the zoom length

 Self experience  amera_and_Photography_Tips_How_Tos_and_Tutorial s.htm amera_and_Photography_Tips_How_Tos_and_Tutorial s.htm  a-camera-phone a-camera-phone   Guide/990/ON-CAMERA-LENS/overview.html Guide/990/ON-CAMERA-LENS/overview.html   a-lenses.htm a-lenses.htm  camera-works.html camera-works.html