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Digital photography



2. GGUUIIDDEEDDBBYYDDrr.. JJIIBBIITTEESSHH MMIISSHHRRAA SSIIRRPPRREESSEENNTTEEDDBBYYRRAAPPAARRTTHHII SSIIVVAA SSAANNKKAARR11MMCCAA//0022 3. CONTENTS If you are in the market for a digital camera,here's the guide you've been looking for. It takes youaround and through the digital camera so you know howit works and what its features are used for. It hashundreds of links to the best sources and products soyou can learn even more. I Hope you enjoy it!1. What is a Digital Photograph?2. Why go digital?3. Image Sensors4. Types of Digital Cameras5. Image Storage 4. 6. Downloading Images7. Image Compression8. Preview Screens & view finders9. Lenses10. Batteries11. Other Features12. Is it Time to Buy?13. The Rules of the Shopping Game14. Digital Photography Web Sites 5. INTRODUCTION Digital photography begins with capturingimages in a digital format. You can do thisby taking photographs with a film cameraand then scanning the slides, negatives, orprints. However, its much faster andeasier to capture images with a digitalcamera. At the moment there are manydigital cameras and new ones seem to beintroduced weekly. If you are at all likeme, these amazing devices are temptingindeed. 6. Its clear that almosteveryone wants to knowmore about whatfeatures to considerwhen buying a cameraand how to use thosefeatures once they ownone. Even if youre anexperiencedphotographer, digitalcameras introduce newcriteria that you have toconsider in your buyingdecision.The Canon S20 7. Straightforward answers to the questions you might have,including the following: Why go digital? What is a digital photograph? How does a digital camera work? What is digital photography? How good are digital cameras? What features should I look for in a digital camera? What resolution do I need? Do I want a point-and-shoot camera or one with creativecontrols? How important are accessories? How should I choose the company to buy from? What alternatives are there to a digital camera? How do I use the features my camera has? 8. 1. WHAT IS A DIGITALPHOTOGRAPH? The digital photograph, is a good place to beginunderstanding the whole digital photographyprocess.PIXELS-DOTS ARE ALL THERE Digital photographs are made up of hundreds ofthousands or millions of tiny squares calledpicture elements-or just pixels. Like theimpressionists who painted wonderful scenes withsmall dabs of paint, your computer and printer canuse these tiny pixels to display or printphotographs. To do so, the computer divides thescreen or printed page into a grid of pixels. Itthen uses the values stored in the digitalphotograph to specify the brightness and color ofeach pixel in this grid-a form of painting bynumber. Controlling, or addressing a grid ofindividual pixels in this way is called bit mappingand digital images are called bit-maps. 9. Here you see a portrait of Amelia Earhart done entirelyin jelly beans. Think of each jelly bean as a pixel and it'seasy to see how dots can form images. 10. Image sizeThe quality of a digital image, whether printed ordisplayed on a screen, depends in part on the numberof pixels used to create the image (sometimesreferred to as resolution). More pixels add detailand sharpen edges.The photo of the face (right)looks normal, but when theeye is enlarged too much(left) the pixels begin toshow. Each pixel is a smallsquare made up of a singlecolor. 11. The size of aphotograph isspecified in one of twoways-by its dimensionsin pixels or by thetotal number of pixelsit contains. Forexample, the sameimage can be said tohave 1800 x 1600pixels (where "x" ispronounced "by" as in"1800 by 1600"), or tocontain 2.88-millionpixels (1800 multipliedby 1600).This digital image of a Monarchbutterfly chrysalis is 1800 pixels wideand 1600 pixels tall. It's said to be1800x1600. 12. 2. WHY GO DIGITAL? Once captured, digitalphotographs arealready in a formatthat makes themincredibly easy todistribute and use. Forexample, you caninsert digitalphotographs into wordprocessing documents,send them by e-mail tofriends, or post themon a Web site whereanyone in the worldcan see them.A small digital camera is easy tocarry so you'll have it when yousee things you never expected tosee. 13. Digital cameras arebecoming more than justcameras. Some digitalcameras are capable ofcapturing not only stillphotographs, but alsosound and even video-theyare becoming more likemultimedia recorders thancameras. In addition to displayingand distributingphotographs, you can alsouse a photo-editingprogram to improve oralter them. For example,you can crop them, removered-eye, change colors orcontrast, and even addand delete elements. It'slike having a darkroomwith the lights on andwithout the chemicals.Once you have captured an image in digitalformat, you can easily distribute, organize,store, and edit it. 14. THE THREE STEPS OF DIGITAL PHOTOGRAPHYStep 1. InputtingphotographsInput devices get photographsor other data into a computersystem. Eg:Digital still camerascapture photographs in a digitalformatStep 2. Processing photographsOnce a photograph is in digital form,you can store it on your system andthen edit or manipulate it with a photo-editingprogram such as Photoshop.Step 3. Outputting photographsOnce an image is the way you want it, youcan output it to share with others. Print theimage on a color printer. 15. If you've been wondering digital photography is spreading faster than anordinary once, here are just some of the reasons. Immediately review your images on the camera's preview screen. Be more confidentbecause you can check your pictures immediately to see if you got what you wanted. Connect the camera to a TV and show your images as a slide show. Connect the camera to a microscope to display dramatically enlarged images on alarge-screen TV. Stitch together panoramas from multiple pictures of the same scene. Print the image on a color printer. Create 3D stereo images to display on the screen. Create animations to display on the screen. Save money by not buying rolls and rolls of film and paying for development. Save time because you don't have to make two trips to the store to drop off and thenpick up your pictures. Choose just the best images for printing. Be an environmentalist by not using the toxic chemicals used in traditionalphotography. Don't wait to finish a roll before having it processed. (Or waste unexposed film whenyou can't wait.) Capture sounds and even short videos with the same camera. Improve or alter your images with a photo-editing program. Hand the camera to the kids, take weird and unusual angles, shoot without lookingthrough the viewfinder. There are no film costs to think about. Insert the photograph into a word processing or desktop publishing document. Post the photograph on a Web site or a photo network. E-mail the photograph to friends or family members. Store the photograph on your system for later use. 16. 3. IMAGE SENSORSDigital cameras are very much like the still more familiar 35mm filmcameras. Both contain a lens, an aperture, and a shutter. The lensbrings light from the scene into focus inside the camera so it canexpose an image. The aperture is a hole that can be made smaller orlarger to control the amount of light entering the camera. The shutter isa device that can be opened or closed to control the length of time thelight enters.Film camera Digital camera 17. The big difference betweentraditional film cameras and digitalcameras is how they capture theimage. Instead of film, digitalcameras use a solid-state devicecalled an image sensor, usually acharge-couple device (CCD). Onthe surface of each of thesefingernail-sized silicon chips is agrid containing hundreds ofthousands or millions ofphotosensitive diodes calledphotosites, photoelements, orpixels. Each photosite captures asingle pixel in the photograph tobe.An image sensor sits against abackground enlargement of itssquare pixels, each capable ofcapturing one pixel in the finalimage. Courtesy of IBM. 18. When the shutteropens, light strikes theimage sensor to formthe image.Courtesy of Canon.The gray scale contains a range of 256 tones from pure white topure black.It may be surprising, but pixels on an image sensor can onlycapture brightness, not color. They record only the gray scale-aseries of 256 increasingly darker tones ranging from pure whiteto pure black. How the camera creates a color image from thebrightness recorded by each pixel is an interesting story. 19. RGB uses additivecolors. When all threeare mixed in equalamounts, they formwhite. When red andgreen overlap, the formyellow, and so on. Tosee how this works,visit Konica'sinteractive presentationby clicking the MoreInfobutton below.WHAT IS COLOR? 20. FROM BLACK ANDWHITE TO COLORSince daylight is made up ofred, green, and blue light,placing red, green, and bluefilters over individual pixels onthe image sensor can createcolor images.Colored filters covereach photosite on theimage sensor so thephotosites only capturethe brightness of the lightthat passes through. Thelenses on top of eachpixel are used to collectlight and make the sensormore sensitive. 21. With the filters in place, each pixelcan record only the brightness ofthe light that matches its filter andpasses through it while other colorsare blocked. For example, a pixelwith a red filter knows only thebrightness of the red light thatstrikes it. To figure out what coloreach pixel really is, a process calledinterpolation uses the colors ofneighboring pixels to calculate thetwo colors that the pixel didn'trecord directly. By combining thesetwo interpolated colors with thecolor measured by the site directly,the full color of the pixel can becalculated. "I'm bright red and thegreen and blue pixels around meare also bright so that must meanI'm really a white pixel."Here the full colorof a green pixel isabout to beinterpolated fromthe eight pixelsthat surround it


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