The Camera http 4 bp blogspot comb Bki

The Camera http: //4. bp. blogspot. com/b. Bki. UB 2 qm. QY/Tii_jx 7 V_2 I/AAAAHhg/Rfn. AEq_k. V 74/s 1600/la wrence_camera_FINAL. jpeg Nathan Hills http: //www. theonlinemom. com/wpcontent/uploads/2014/02/smartphone-camera-425. jpg

Overview Introduction General Description History Relevant Optics Diffraction and Aperture (f-number) Refraction and Lenses Depth of Field Shutter f-number Equation Example Problem Conclusion Camera’s in science Camera’s in society

General Description (Serway) The photographic camera is an optical instrument that consists of a lighttight chamber, converging lens that produces a real image, and a film (or chargecoupled device) behind the lens to receive the image. (Serway)

History “For several centuries, people amused themselves with cameras of various kinds, from small portable models used as artists’ aids, to large rooms you could enter and see realistic, moving, full color projections of the scenery and life going on outside. ” (Falk) http: //pixsylated. com/blog/stepping-inside-havana-camera-obscura/

ca. 470 to ca. 391 BC - First mentions of camera obscura (Latin for “dark room”) date back to Chinese philosopher Mozi (“Cellphone Cameras”) 1727 – Johann Heinrich Schulze discovers substances mixed with silver nitrate react to light, but image’s fade soon after. ("Johann Heinrich Schulze. ”) soon after. ( 1826 – First photograph by Joseph Nicephore Niepce in France (takes several days of light exposure) (“Cellphone Cameras”) 1833 – Louis Daguerre creates first practical photo process and names device the “Daguerreotype”. (“Cellphone Cameras”) 1839 – France buys Daguerreotype and declares it free to the world (also first photo of a human is around this time) (“Cellphone Cameras”)

1888 – First Kodak camera was placed on the market, with the sloga, “You press the button- we do the rest. ” This was the birth of snapshot photography. ("MILESTONES. ”) was the birth of snapshot photography. ( 1975 –Kodak creates the first digital camera (CCD instead of film) turning photographs into binary code to be stored for later use. ("MILESTONES. ”) for later use. ( 2000 – The SCH-V 200 by Samsung becomes first camera phone. 2007 – i. Phone released giving a convenient way to share photo’s to the world. Today – Virtually everyone has a camera in their pocket.

Diffraction and Aperture (f-number) Diffraction - the process by which a beam of light or other systems of waves is spread out as a result of passing through a narrow aperture or across an edge” (Google search - “Diffraction”) http: //www. schoolphysics. co. uk/age 14 -16/Wave%20 properties/text/Diffraction_/index. html

(What Is Lens Diffraction) Aperture is analogous to the pupil of an eye. How open or closed the aperture determines the amount of light that can pass through the lens. f-number is a way to represent aperture. Notice that smaller f-number = larger aperture.

(What Is Lens Diffraction) A large aperture (small f-number) on the left means light can hit the film straight on giving a clear image. A small aperture (large f-number) on the right causes the light to diffract and spray out in a way that the light doesn’t produce a precise image. Side note - Doubling the f-number reduces the amount of light through the lens by one half

Refraction and Lenses Refraction, in physics, is the change in direction of a wave passing from one medium to another caused by it’s change in speed. (“Refraction”) Due to speed change NOT frequency change. Frequency is an inherent characteristic of the wave once it leaves the source. n – refractive index (inherent of medium) V – wave velocity λ- wavelength https: //www. sciencelearn. org. nz/resources/49 -refraction-of-light

Types of Lenses DIVERGING: The image is always virtual and located between the object and the lens. (Serway) CONVERGING: As long as the object is outside the focal point the image is real and inverted. Inside the focal point, image is virtual and upright. (Serway) http: //www. nightlase. com. au/education/optics/lenses. htm

Camera’s use Converging Lenses http: //www. ohioimpact. org/index. php/2015/08/06/how-to-create-a-focal-point-in-any-room/ Changing the distance from the lens to the film (or CCD) allows the image to be focused, which we will see is one way to adjust the depth of field.

Depth of Field (DOF) “The distance between the nearest object and the furthest objects that give an image judged to be in focus in the camera” (Google Search – “Depth of field”) https: //cdn. photographylife. com/wp-content/uploads/2016/12/Do. F-sketch. jpg

Three ways to change DOF 1. Distance to Subject 2. Focal Length 3. Aperture Large Far Short Small (large opening) Narrow Close Long Large (small opening)

Shutter The shutter is a mechanical device opened for time intervals called “exposure times” In practice, stationary objects are normally shot with an intermediate shutter speed of 1/60 th second. (Serway) Moving objects need short time intervals 1/2000 th – 1/4000 th second can stop a hummingbird Dark sceneries need long time intervals Allows more light to hit the film/CCD

f-number equation (Serway) Formal derivation can be seen our physics textbook pg 1031. Basically proves that intensity is proportional to diameter of the lens (changed by aperture) and inversely proportional to the focal length (q in picture)(Serway). This leads to a simple equation: f-number = focal length/exposed lens diameter f-number = f/D

More on f-numbers Camera lens systems are often marked with multiple fnumbers, usually f/2. 8, f/4, f/5. 6, f/11, f/16. Anyone of these settings can be selected by adjusting the aperture, which changes the value of D (Serway). F-number equation rearranged: D=f/f-number

Example from Serway text The lens of a digital camera has a focal length of 55 mm and a speed (an f-number) of f/1. 8. Determine the diameter of the lens. D = f/f-number = 55 mm/1. 8 = 31 mm

Camera’s in Science • Photographs provide a record of scientific information. • Record the presence of clouds, contrails, plants, insects, birds, reptiles and other animals. • Photographs of specific scenes can be compared with photographs made months or even years earlier or later to look for changes, such as the growth of trees. • Photographs of unusual events and phenomena can provide important information to scientists. ("Doing Science with a Camera…)

Camera’s in Society In society, camera’s allow us to take part in history. “Photographs open doors to the past, but they also allow us to look into the future” – Sally Mann

(http: //www. boredpanda. com/top-100 -world-photos-influential-all-time/? page_numb=2)

(http: //people. com/politics/trump-obama-situation-room-photos-compared/)

“Earthrise” (https: //www. nasa. gov/multimedia/imagegallery/image_feature_1249. html)

“Pale Blue Dot” (https: //blogs. scientificamerican. com/life-

Bibliography "Cellphone Cameras. " Access. Science (n. d. ): n. pag. Sennhs. org. Web. 29 May 2017. http: //www. sennhs. org/ourpages/auto/2013/4/1/41446028/The%20 Birth%20 of%20 Cameras. pdf "Doing Science with a Camera - MY NASA DATA. " NASA, n. d. Web. 27 May 2017. https: //mynasadata. larc. nasa. gov/science_projects/doing-science-with-a-camera Falk, David S. , Dieter R. Brill, and David G. Stork. "The Camera and Photography. " Seeing the Light: Optics in Nature, Photography, Color, Vision, and Holography. Chichester: Wiley, 2008. 107. Print. "Johann Heinrich Schulze. " Encyclopædia Britannica, Inc. , n. d. Web. 28 May 2017. https: //www. britannica. com/biography/Johann-Heinrich-Schulze "MILESTONES. " Milestones | Kodak. N. p. , n. d. Web. 01 June 2017. http: //www. kodak. com/corp/aboutus/heritage/milestones/default. htm Serway, Raymond A. , and John W. Jewett. "Image Formation. " Physics for Scientists and Engineers with Modern Physics. 7 th ed. Australia: Thomson/Brooks/Cole, 2008. 1031 -032. Print. The Editors of Encyclopædia Britannica. "Refraction. " Encyclopædia Britannica, Inc. , n. d. Web. 30 May 2017. https: //www. britannica. com/science/refraction. What Is Lens Diffraction and How Does It Affect DSLR Photography. Perf. Patrick Hall. Youtube. Fstoppers, n. d. Web. https: //youtu. be/ka. GJjf_q. O 9 M.