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Chapter 3
Lenses
Objectives
Information in this chapter will enable you to:
• List two simple rules of light and optics.
• Defi ne transmitted light and tell why it is
important to photography.
• Describe the types of lenses and how each
transmits light.
• Explain focal length, aperture, and f-numbers.
• Describe different types of lens mounts.
• Describe the proper method of cleaning a lens.
• Describe how to change lenses while
minimizing the amount of dust getting in the
camera.
Technical Terms
aberrations
angle of view
bayonet lens mount
compound lens
convergent lens
crop factor
divergent lens
element
fast lens
f-number
f-stop
focal length
focal plane
focus
image point
image size
incident light
lens
lens aperture
lens mount
magnifi cation
negative lens
normal lens
optics
positive lens
refraction
screw mount lens
single-touch zoom lens
stopping down
two-touch zoom lens
zoom lens