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23 Cards in this Set
- Front
- Back
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Lenses adding convergence to light rays
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are plus
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lenses adding divergence to light rays
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are minus
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all distance to left or in front of a lens are
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negative
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all distance to right or behind the lens are
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positive
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what is U in the equation U + D =V
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vergence of light entering the lens (in diopters)
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What is V in the equation U+D=V
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vergence of light exiting the lens (in diopters)
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What is D in the equation U+D=V
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dioptric power of the lens
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How do we solve for distance when given diopters
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D=1/m
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Define a real image
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a real image is formed by converging light rays. can be projected onto a screen, and is on the same side as the outgoing light rays
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define a real object
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a real object is on the same side as the incoming light rays
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Define a virtual image
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is created by light rays diverging from an optical system and extrapolated back to the image point, they canot be focused onto a screen, and are located on the opposite side as the outgoing light rays
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Define a virtual object
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object is on the opposite side as the incoming light rays
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define the primary focal point
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this is the point where an object must be placed so that the given lens will form an image at infinity (V=0)
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how does primary focal point work for a plus lens
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at some point in front of a lens the negative value of the diverging light rays from that point will match the dioptric power of the lens and light rays will exit parallel
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how does primary focal point work for a minus lens
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in order to have light rays exciting a minus lens (which adds divergence) parallel it is necessary to have the light converging as it enters the lens
the first focal point is an imaginary point where those converging rays would meet if they had not been intercepted by the lens, the distance between the focal point and the lens is the focal length |
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what is the focal length of a -3.25 lens
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U + D=V
U + -3.25 =0 U= +3.25 F= 1/D =1/3.25 = +0.308 m |
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What is the second focal length
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this is the point where an image will be formed by a given lens when the object is at infinity U=0,
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for a minus lens a real image will be formed.....
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behind the lens at the focal point
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for a minus lens a virtual will be formed....
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in front of the lens
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what is the second focal length of a +1.25
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U + D=V
0+1.25 =V V= 1.25 F= 1/D =1/1.25 = + .8m |
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what is the nodal point
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defined as the axial point at which object rays and image subtend at identical angles (undeviated)
optical center |
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what are the three magnification formulas to remember
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M=I/O I-image size, O-Object size
m=v/u v- distance from lens to image, u-distance from object to lens m=U/V U- vergences of light, in diopters, entering lens V- vergences of light in diotpers exiting lens |
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anything over and under 1 in m= U/V means what?
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anything over 1 will be perceived larger, where anything under 1 will be perceived smaller
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