Upcoming Classes Thursday, Nov. 15 th Optics and Photography Special Guest: Prof. Brian Taylor,...
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Transcript of Upcoming Classes Thursday, Nov. 15 th Optics and Photography Special Guest: Prof. Brian Taylor,...
Upcoming Classes
Thursday, Nov. 15th
Optics and Photography
Special Guest: Prof. Brian Taylor, Photography, SJSU
Assignment due:
* Read “The Camera and Photograph, Seeing the Light : Optics in Nature, Photography, Color, Vision, and
Holography, D. Falk, D. Brill, & D. Stork, Pages 107-117
* Topic and Outline for Third Paper/Presentation
Tuesday, Nov. 20th
To Be Announced
Upcoming Deadlines
Thursday, November 15th
Outline of third oral presentation or written paper
Tuesday, December 4th
Third Set of Oral Presentations
Third term paper (if not presenting)
Oral Presentations (III)
The following persons will give oral presentations on Tuesday, December 4th :
• Remmel, Katherine• Sugiura, Ayuka• Yamaguchi, Asuka• Zeber, Emily,• Dinh, Phiphi
For everyone else, term paper is due on that date.
Extra Credit: Beethoven Center
Visit the Beethoven Center on the Fifth floor of MLK library.
Take a photo of yourself with one of the pianos or harpsichords.
Turn in photo by Thurs., Nov. 15th for one quiz worth of extra credit.
Extra Credit: San Jose Ballet
See a performance of San Jose Ballet in San Jose Center for Performing Arts (Nov. 15th – 18th ).
Turn in your ticket receipt. Worth one homework assignment or three quiz/participation credits.
Ramon Moreno in CARMINA BURANA
Refraction
Light rays bend (refract) passing from water to air, making objects appear to be shallower and closer to the observer.
Image
Actual
Image
Actual
Observer sees image
Law of Refraction
Light passing from one material to another is refracted by a fractional angle that depends on the optical density of each material.
Angle is smaller in the denser material.
Demo: Refraction thru Block
Light is refracted entering the block and refracted back on leaving the block.
Check Yourself
Which path does light ray take after entering the wedge?
Path B
Which path does it take after leaving the wedge?
Path F
A
B
C
D
E
F
WEDGE
Optical Density
Air
Water
Air
Glass
Air
Diamond
n = 1.3
n = 1.0
n = 1.5
n = 1.0
n = 2.4
n = 1.0
Optical density is measured by the index of refraction, n.
The larger the difference between the indices at an interface, the larger the angle of refraction for light rays crossing the interface.
Demo: Invisibility
Mineral oil and glass have nearly the same index of refraction
A glass rod is nearly invisible in a beaker of mineral oil.
A diamond, however, is easily seen.
Separating Colors
Blue wavelength of light refracts slightly more than the red, creating rainbows.
Glass Prism
WaterDroplet
Rainbows
Rainbows are formed by refraction from many, many raindrops. The red part is always above the blue part.
Total Internal Reflection
When refraction angle exceeds 90º the light does not cross the surface.
Refracted
ReflectedReflected
Apr 19, 2023 Physics 1 (Garcia) SJSU
Demo: Total Internal Reflection
Past the critical angle all the light is internally reflected.
Just below critical angle
Apr 19, 2023 Physics 1 (Garcia) SJSU
Demo: Total Internal Reflection
Prism demonstrates total internal reflection if the angle of incidence is large enough.
Apr 19, 2023 Physics 1 (Garcia) SJSU
Looking up Underwater
Try this when you’re in the pool this summer
Looking straight up you see the sky but outside the 96° cone surface is like a mirror
Apr 19, 2023 Physics 1 (Garcia) SJSU
Fiber OpticsTotal internal reflection
causes light to reflect inside a solid glass tube.
Diamond Cuts
Diamonds are cut so as to create a beautiful jewelry by taking advantage of total internal reflection and high color dispersion (prism effect).
Lenses
Curvature of a lens surface produces a continuous, variable angular refraction.
Concave lens shrinks its image
Convex lens magnifies its image
Demo: Concave Lenses
Curved surface of a concave lens causes light rays to diverge, shrinking images.
Demo: Convex Lenses
Curved surface of a convex lens causes light rays to converge, magnifying images
Pinhole Camera
Small pinhole allows only small amount of light in, blocking overlapping diffuse rays and forming image inside the camera.
Demo: Pinhole Lens
Make a small pinhole in a piece of cardboard. You’ll find that you can focus better when looking through the pinhole.
ETGWRPOCVMXSRYUQBNEHDThis works best if you
remove any corrective lenses, such as contacts and eyeglasses.
Camera ObscuraThe camera obscura (room darkened) dates to ancient times; it was
first detailed in the writings of Leonardo da Vinci. A room is completely sealed from light except for a coin-sized hole in
one wall. An image of the outside world appears projected, upside down and reversed right-to-left, onto a wall opposite the opening.
Diffuse light
Giant Camera
Camera obscura with a projecting mirror.
Next to the Cliff House, San Francisco
Mirror
Mirror
Johannes Vermeer (1632-75)Common elements in his paintings and ray tracing
analysis suggest that this great Dutch artist may have built a camera obscura in his studio.
The Music Lesson
Camera Lens
Using a lens allows for more light to be focused on the camera screen or film.
No image (Diffuse) Camera obscura Camera with lens
Eye Lens
The eye’s lens changes shape to focus the image onto light sensitive cells of retina.
Image is formed upside-down on the retina.
Visual Acuity
If eye’s lens is unable to form image on the retina, an object will appear out of focus.
Myopia Hyperopic
Eyeglasses
Lenses of eyeglasses restore visual acuity by combining with the eye’s lens to form focused image onto retina.
Eyeglasses began to appear in common use in the 13th century. They may have been invented in northern Italy but Marco Polo reports them in China as early as 1275.
Detail of portrait of Hugh de Provence, Tomasso da Modena, 1352
Pinhole glasses
Astigmatism
Astigmatism due to eye’s lens being elliptical, which causes the focus in the vertical to differ from horizontal.
Vertical focus
Astigmatism may be corrected using a cylindrical lens.In this example, the lens focuses in the horizontal only since vertical is already in focus.