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digital photography

Text of Dig -Photography

  • 2/10/2015 DigitalphotographyWikipedia,thefreeencyclopedia

    http://en.wikipedia.org/wiki/Digital_photography 1/12

    NikonD700a12.1megapixelfullframeDSLR

    TheCanonPowerShotA95

    DigitalphotographyFromWikipedia,thefreeencyclopedia

    Digitalphotographyisaformofphotographythatusescamerascontainingarraysofelectronicphotodetectorstocaptureimagesfocusedbyalens,asopposedtoanexposureonphotographicfilm.Thecapturedimagesaredigitizedandstoredasacomputerfilereadyforfurtherdigitalprocessing,viewing,digitalpublishingorprinting.

    Untiltheadventofsuchtechnology,photographsweremadebyexposinglightsensitivephotographicfilm,andusedchemicalphotographicprocessingtodevelopandstabilizetheimage.Bycontrast,digitalphotographscanbedisplayed,printed,stored,manipulated,transmitted,andarchivedusingdigitalandcomputertechniques,withoutchemicalprocessing.

    Digitalphotographyisoneofseveralformsofdigitalimaging.Digitalimagesarealsocreatedbynonphotographicequipmentsuchascomputertomographyscannersandradiotelescopes.Digitalimagescanalsobemadebyscanningotherphotographicimages.

    Sincethe2000sdigitalphotographyhaslargelysupersededallotherformsofphotography.

    Contents

    1Thedigitalcamera1.1History1.2Sensors1.3Multifunctionalityandconnectivity1.4Performancemetrics

    1.4.1Pixelcounts1.4.2Dynamicrange

    1.5Storage2Marketimpact

    2.1Socialimpact3Recentresearchandinnovation4Comparisonwithfilmphotography

    4.1Consumercameras4.2Advantagesofprofessionaldigitalcameras4.3Disadvantagesofdigitalcameras4.4Equivalentfeatures

    http://en.wikipedia.org/wiki/Image_scannerhttp://en.wikipedia.org/wiki/Digital_publishinghttp://en.wikipedia.org/wiki/Photographic_filmhttp://en.wikipedia.org/wiki/Computer_tomographyhttp://en.wikipedia.org/wiki/Photographic_processinghttp://en.wikipedia.org/wiki/Digital_imaginghttp://en.wikipedia.org/wiki/Nikon_D700http://en.wikipedia.org/wiki/Digital_imagehttp://en.wikipedia.org/wiki/Computerhttp://en.wikipedia.org/wiki/Photographic_filmhttp://en.wikipedia.org/wiki/Electronicshttp://en.wikipedia.org/wiki/Nikonhttp://en.wikipedia.org/wiki/Radio_telescopehttp://en.wikipedia.org/wiki/Photodetectorhttp://en.wikipedia.org/wiki/Digitizinghttp://en.wikipedia.org/wiki/File:Canon_powershot_a95.jpghttp://en.wikipedia.org/wiki/Canon_PowerShot_Ahttp://en.wikipedia.org/wiki/Lens_(optics)http://en.wikipedia.org/wiki/Computer_filehttp://en.wikipedia.org/wiki/File:D700-400.jpg

  • 2/10/2015 DigitalphotographyWikipedia,thefreeencyclopedia

    http://en.wikipedia.org/wiki/Digital_photography 2/12

    4.5Frameaspectratios5Seealso6References7Externallinks

    Thedigitalcamera

    History

    ThefirstflybyspacecraftimageofMarswastakenfromMariner4onJuly15,1965withacamerasystemdesignedbyNASA/JPL.Itusedavideocameratubefollowedbyadigitizer,ratherthanamosaicofsolidstatesensorelements,soitwasnotwhatweusuallydefineasadigitalcamera,butitproducedadigitalimagethatwasstoredontapeforlaterslowtransmissionbacktoearth.[1][2]

    Thefirstrecordedattemptatbuildingadigitalcamerawasin1975byStevenSasson,anengineeratEastmanKodak.[3][4]ItusedthethennewsolidstateCCDimagesensorchipsdevelopedbyFairchildSemiconductorin1973.[5]Thecameraweighed8pounds(3.6kg),recordedblackandwhiteimagestoacassettetape,hadaresolutionof0.01megapixels(10,000pixels),andtook23secondstocaptureitsfirstimageinDecember1975.Theprototypecamerawasatechnicalexercise,notintendedforproduction.

    ThefirsttruedigitalcamerathatrecordedimagesasacomputerizedfilewaslikelytheFujiDS1Pof1988,whichrecordedtoa16MBinternalmemorycardthatusedabatterytokeepthedatainmemory.Thiscamerawasnevermarketedinternationally,andhasnotbeenconfirmedtohaveshippedeveninJapan.

    Thefirstcommerciallyavailabledigitalcamerawasthe1990DycamModel1italsosoldastheLogitechFotoman.ItusedaCCDimagesensor,storedpicturesdigitally,andconnecteddirectlytoacomputerfordownloadingimages.[6][7][8]

    Sensors

    Imagesensorsreadtheintensityoflight,anddigitalmemorydevicesstorethedigitalimageinformationasRGBcolorspaceorasrawdata.

    Thetwomaintypesofsensorsarechargecoupleddevices(CCD),inwhichthephotochargeisshiftedtoacentralchargetovoltageconverter,andCMOSoractivepixelsensors.

    Multifunctionalityandconnectivity

    Exceptforsomelineararraytypeofcamerasatthehighestendandsimplewebcamsatthelowestend,adigitalmemorydevice(usuallyamemorycardfloppydisksandCDRWsarelesscommon)isusedforstoringimages,whichmaybetransferredtoacomputerlater.

    Digitalcamerascantakepictures,andmayalsorecordsoundandvideo.Somecanbeusedaswebcams,somecanusethePictBridgestandardtoconnecttoaprinterwithoutusingacomputer,andsomecandisplaypicturesdirectlyonatelevisionset.Similarly,manycamcorderscantakestillphotographs,andstorethemonvideotapeoronflashmemorycardswiththesamefunctionalityasdigitalcameras.

    http://en.wikipedia.org/wiki/Digital_camerahttp://en.wikipedia.org/wiki/Raw_image_formathttp://en.wikipedia.org/wiki/CD-RWhttp://en.wikipedia.org/wiki/Web_camhttp://en.wikipedia.org/wiki/Computerhttp://en.wikipedia.org/wiki/Active_pixel_sensorhttp://en.wikipedia.org/wiki/Videotapehttp://en.wikipedia.org/wiki/Mariner_4http://en.wikipedia.org/wiki/Floppy_diskhttp://en.wikipedia.org/wiki/Charge-coupled_devicehttp://en.wikipedia.org/wiki/Digital_memoryhttp://en.wikipedia.org/wiki/Camcorderhttp://en.wikipedia.org/wiki/Charge-coupled_devicehttp://en.wikipedia.org/wiki/Logitechhttp://en.wikipedia.org/wiki/Image_sensorhttp://en.wikipedia.org/wiki/Fujifilmhttp://en.wikipedia.org/wiki/Image_sensorhttp://en.wikipedia.org/wiki/Video_camera_tubehttp://en.wikipedia.org/wiki/Steven_Sassonhttp://en.wikipedia.org/wiki/Fairchild_Semiconductorhttp://en.wikipedia.org/wiki/PictBridgehttp://en.wikipedia.org/wiki/Digital_memoryhttp://en.wikipedia.org/wiki/RGB_color_spacehttp://en.wikipedia.org/wiki/Intensity_(physics)http://en.wikipedia.org/wiki/Image_sensorhttp://en.wikipedia.org/wiki/Webcamhttp://en.wikipedia.org/wiki/CMOShttp://en.wikipedia.org/wiki/Memory_cardhttp://en.wikipedia.org/w/index.php?title=DS-1P&action=edit&redlink=1http://en.wikipedia.org/wiki/Flash_memory

  • 2/10/2015 DigitalphotographyWikipedia,thefreeencyclopedia

    http://en.wikipedia.org/wiki/Digital_photography 3/12

    Imageatlefthasahigherpixelcountthantheonetotheright,butlowerspatialresolution.

    Performancemetrics

    Thequalityofadigitalimageisacompositeofvariousfactors,manyofwhicharesimilartothoseoffilmcameras.Pixelcount(typicallylistedinmegapixels,millionsofpixels)isonlyoneofthemajorfactors,thoughitisthemostheavilymarketedfigureofmerit.Digitalcameramanufacturersadvertisethisfigurebecauseconsumerscanuseittoeasilycomparecameracapabilities.Itisnot,however,themajorfactorinevaluatingadigitalcameraformostapplications.Theprocessingsysteminsidethecamerathatturnstherawdataintoacolorbalancedandpleasingphotographisusuallymorecritical,whichiswhysome4+megapixelcamerasperformbetterthanhigherendcameras.

    Resolutioninpixelsisnottheonlymeasureofimagequality.Alargersensorwiththesamenumberofpixelsgenerallyproducesabetterimagethanasmallerone.Oneofthemostimportantdifferencesisanimprovementinimagenoise.ThisisoneoftheadvantagesofdigitalSLRcameras,whichhavelargersensorsthansimplercameras(socalledpointandshootcameras)ofthesameresolution.

    Lensquality:resolution,distortion,dispersion(seeLens(optics))Capturemedium:CMOS,CCD,negativefilm,reversalfilmetc.Captureformat:pixelcount,digitalfiletype(RAW,TIFF,JPEG),filmformat(135film,120film,5x4,10x8).Processing:digitaland/orchemicalprocessingof'negative'and'print'.

    Pixelcounts

    Thenumberofpixelsnforagivenmaximumresolution(whorizontalpixelsbyhverticalpixels)istheproductn=wh.Thisyieldse.g.1.92megapixels(1,920,000pixels)foranimageof16001200.ThemajorityofcompactaswellassomeDSLRcamerashavea4:3aspectratio,i.e.w/h=4/3.[9]AccordingtoDigitalPhotographyReview,the4:3ratioisbecause"computermonitorsare4:3ratio,oldCCDsalwayshada4:3ratio,andthusdigitalcamerasinheritedthisaspectratio."[9]

    Thepixelcountquotedbymanufacturerscanbemisleadingasitmaynotbethenumberoffullcolorpixels.Forcamerasusingsinglechipimagesensorsthenumberclaimedisthetotalnumberofsinglecolorsensitivephotosensors,whethertheyhavedifferentlocationsintheplane,aswiththeBayersensor,orinstacksofthreecolocatedphotosensorsasintheFoveonX3sensor.However,theimageshavedifferentnumbersofRGBpixels:BayersensorcamerasproduceasmanyRGBpixelsasphotosensorsviademosaicing(interpolation),whileFoveonsensorsproduceuninterpolatedimagefileswithonethirdasmanyRGBpixelsasphotosensors.Comparisonsofmegapixelratingsofthesetwotypesofsensorsaresometimesasubjectofdispute.[10]

    Therelativeincreaseindetailresultingfromanincreaseinresolutionisbettercomparedbylookingatthenumberofpixelsacross(ordown)thepicture,ratherthanthetotalnumberofpixelsinthepicturearea.Forexample,asensorof25601600sensorelementsisdescribedas"4megapixels"(25601600=4,096,000).Increasingto32002048increasesthepixelsinthepictureto6,553,600(6.5

    http://en.wikipedia.org/wiki/120_filmhttp://en.wikipedia.org/wiki/Image_noisehttp://en.wikipedia.org/wiki/TIFFhttp://en.wikipedia.org/wiki/Image_resolutionhttp://en.wikipedia.org/wiki/Pixelhttp://en.wikipedia.org/wiki/Megapixelhttp://en.wikipedia.org/wiki/135_filmhttp://en.wikipedia.org/wiki/JPEGhttp://en.wikipedia.org/wiki/Raw_image_formathttp://en.wikipedia.org/wiki/Spatial_resolutionhttp://en.wikipedia.org/wiki/Image_sensorhttp://en.wikipedia.org/wiki/Pixel_counthttp://en.wikipedia.org/wiki/Image_distortionhttp://en.wikipedia.org/wiki/Demosaicinghttp://en.wikipedia.org/wiki/Aspect_ratio_(image)http://en.wikipedia.org/wiki/Negative_filmhttp://en.wikipedia.org/wiki/Digital_single-lens_reflex_camerahttp://en.wikipedia.org/wiki/Pixelhttp://en.wikipedia.org/wiki/Figure_of_merithttp://en.wikipedia.org/wiki/File:MARTAKIS1.jpghttp://en.wikipedia.org/wiki/File:Matakis_-_blurred.jpghttp://en.wikipedia.org/wiki/Foveon_X3_sensorhttp://en.wikipedia.org/wiki/Bayer_sensorhttp://en.wikipedia.org/wiki/Dispersion_(optics)http://en.wikipedia.org/wiki/