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.

Homework 5: Exploratorium

Due Thursday, November 29th

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

Lenses & The Eye

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.

Double Rainbow

Primary

Secondary

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

Demo: Real Image of Convex Lens

Image formed by convex lens can be observed on a screen.

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

Vermeer

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.

Next Lecture Optics & Photography

Assignment due:

* Read “The Camera and Photograph”, in Seeing the Light : Optics in Nature, Photography, Color, Vision, and Holography, D. Falk, D. Brill, & D. Stork, Pages 107-117

* Topic and Outline of Third Paper or Presentation