Section 4.1: Image Section 4.1: Image Formation in Eyes and Formation in Eyes and

Cameras Cameras

http://www.imaging-resource.com/PRODS/E50D/E50DA.HTM

http://www.eyedoctorguide.com/eye_care/eye_pupil.html

Class WebsiteClass Website

http://mrspilipchuk.weebly.com

I CAN…I CAN…I can explain the use of concave and convex lenses in objects, such as cameras and eyeglasses.

Concave and Convex Concave and Convex LensesLenses

http://www.daviddarling.info/childrens_encyclopedia/light_Chapter4.html

How Light Gets InHow Light Gets In

Both eyes (natural) and cameras (artificial) are image-producing technologies.

A camera is very similar to how an eye works.

http://photoity.com/top-10-digital-cameras-for-photography-geeks/

Structures and Structures and FunctionsFunctions

Eye Camera

Anatomy of a CameraAnatomy of a Camera and an Eye and an Eye

Similarities Between a Similarities Between a Camera and an Eye Camera and an Eye

Human Eye

Camera

How does light enter?

Pupil Aperture

What controls the amount of light?

Iris Diaphragm

What interprets the image?

Retina Film

How is the light focused?

Lens Lens

Eye AnatomyEye Anatomy

The pupil is the opening; the amount of light that enters is controlled by the iris.

The iris is made up of a circular band of muscles.

http://perspectiveopticians.co.uk/2011/11/25/anatomy-of-your-eye/

Iris Controls the Light Iris Controls the Light

In bright light the iris constricts, becoming smaller, and reduces the light.

In dim light the iris dilates, becoming larger and increases the light.

http://www.thenakedscientists.com/forum/index.php?topic=50610.0

When Light Gets Inside…When Light Gets Inside…To see, the light must hit the sensitive

retina at the back of the eye, which has 2 types of light-sensitive photoreceptors:

1) Rods and 2) Cones

RodsHighly sensitive to small amounts of

light (dim light).Allows for seeing in the dark (when

there is enough light reflected).More rods on the outside of the retina.

Sensitive to bright lights, and they detect colour.

Almost exclusively in the retina.

Patcharaporn Ch. Own Work. http://www.gamefaqs.com/boards/640108-assassins-creed-iii-liberation/64500498

Cones

Rods and ConesRods and Cones

Cones can’t function in low light, so we only see shades of grey in low light because only rods are stimulated.

http://hypervocal.com/entertainment/2012/sinfully-crafty-diy-projects-inspired-by-fifty-shades-of-grey/

https://whin111.wordpress.com/page-5-the-light-is-on-albeit-dim/

Give it a Try Give it a Try (p. 233)(p. 233)

www.sciencewithme.com

Focusing the LightFocusing the LightIn order to form a clear and sharp

image, the focal point must land on the retina.

In the eye there are muscles that control the shape of the lens.

Images ProducedImages Produced

In a camera the lens is moved forward and backward.

The upside-down image produced by the lens is not a problem because the brain interprets the world right-side up, and film can be developed either way.

http://www.eetimes.com/author.asp?doc_id=1284549

Correcting Vision ProblemsCorrecting Vision Problems

Nearsightedness (Myopia) Image falls short of the retina. Trouble seeing distant objects. Corrected with concave lenses.

https://www.koofers.com/links/nearsightedness-test-do-you-see-einstein-or-

marily/

http://en.wikipedia.org/wiki/Myopia#mediaviewer/File:Myopia.gif

Correcting Vision ProblemsCorrecting Vision Problems

Farsightedness (Hyperopia) Image falls behind the retina. Trouble seeing near objects. Corrected with convex lenses.

http://www.bausch.com/your-eye-concerns/vision-correction/farsightedness-hyperopia#.VOgJqFPF8mc

ReviewReview

Can be corrected with a concave lens.

Can be corrected with a convex lens.

AstigmatismAstigmatismAstigmatism Video

http://www.lasikmd.com/edmonton/candidate/eye-problems/astigmatism

ReviewReview

Normal Vision and Vision Problems

Reading Between the Lines Activity

Laser Eye SurgeryLaser Eye SurgeryThe lens is reshaped by a laser,

which helps focus light.

Lasik surgery

Night Vision GogglesNight Vision GogglesLow light is

intensified by phosphor-coated screen.

Looks green

http://rhode.meccahosting.com/~a0008087/Yukon%20Tracker%201x24%20Night%20Vision

%20Goggle%20Kit%20YK25025.htm

http://bestnightvisionbinocular.blogspot.ca/2015/01/exactly-whats-so-great-about-night.html

HomeworkHomeworkCheck and Reflect #2 (p. 235).

Go to Mrs. Pilipchuk’s website and print off the handout for section 4.2 for next class.

Differences Between a Differences Between a Camera and an EyeCamera and an Eye

Human Eye Camera

Flexible eyeball•Filled with fluids

Rigid camera body•Light proof box

Flexible lens•Controlled by muscles

Solid lens•Not flexible

Rods and cones•Specialized cells which send images to the brain.

Silver compound in film•Retains image

Red EyeRed Eye

http://en.wikipedia.org/wiki/Red-eye_effect