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Digital Camera Basics NCLA Workshop


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Workshop presented by Emily Gore and Amy Rudersdorf at NCLA 2007

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Digital Camera Basics NCLA Workshop

  1. 1. Digital Camera Basics Amy Rudersdorf, NC State University Libraries Emily Gore, NC ECHO
  2. 2. Digital Camera Basics <ul><li>First half: mechanics of camera </li></ul><ul><ul><li>Printed materials offer a basic guide </li></ul></ul><ul><li>Second half: capture and lighting </li></ul><ul><ul><li>Learning curve with digital camera </li></ul></ul><ul><ul><li>“ Craft of lighting” can take a lifetime to master </li></ul></ul>
  3. 3. Digital Camera Basics: Mechanics <ul><li>Digital camera definition </li></ul><ul><ul><li>A (primarily) still camera that captures images as discrete numbers (as opposed to variable intensities of light) by an array of charge-coupled devices (CCDs) </li></ul></ul><ul><ul><li>There is a fixed maximum resolution and number of colors that can be represented </li></ul></ul>
  4. 4. Digital Camera Basics: Mechanics <ul><li>Analog photography </li></ul><ul><ul><li>Negative or slide film is medium of capture </li></ul></ul><ul><li>Digital photography </li></ul><ul><ul><li>The “film” is a light sensor* </li></ul></ul><ul><li>*Either a CCD (charge-coupled device) or CMOS (complementary metal oxide semiconductor) </li></ul>
  5. 5. Digital Camera Basics: Mechanics <ul><li>Light sensors </li></ul><ul><ul><li>Convert light into thousands [or millions] of pixels </li></ul></ul><ul><ul><li>Pixels are tiny “dots” in which color/light data is stored </li></ul></ul><ul><li>Capture occurs at single moment when shutter opens and closes </li></ul>
  6. 6. Digital Camera Basics: Mechanics <ul><li>Digital camera types </li></ul><ul><ul><li>Point & shoot (P&S) </li></ul></ul><ul><ul><li>Single lens reflex (SLR) </li></ul></ul><ul><ul><li>Overhead/stationary </li></ul></ul><ul><ul><li>“Scan backs” </li></ul></ul>
  7. 7. Point & Shoot (P&S): Digital Cameras <ul><li>Adjusts settings such as focus and exposure automatically </li></ul><ul><li>Some P&Ss offer manual controls </li></ul><ul><li>Compact </li></ul><ul><li>Typically has LCD* screen; may have viewfinder </li></ul><ul><li>LCD screen is excellent because it reduces image to two-dimensional view </li></ul>*Liquid crystal display
  8. 8. Single-lens reflex (SLR): Digital Cameras <ul><li>“Professional-level” cameras </li></ul><ul><li>View image through viewfinder </li></ul><ul><ul><li>Much better for action, but limits the user to viewing through camera </li></ul></ul><ul><li>Interchangeable lenses, higher quality optics </li></ul><ul><li>Larger than P&Ss </li></ul><ul><li>High ISO (light sensitivity) </li></ul><ul><li>Shutter response is faster than P&Ss </li></ul>
  9. 9. Single-lens reflex (SLR): Digital Cameras <ul><li>Mirror behind the lens reflects light coming into camera onto a ground glass screen </li></ul><ul><li>View through lens is seen through viewfinder </li></ul><ul><li>As shutter button is pressed, mirror lifts away to allow the light to reach image sensor and board where image is captured </li></ul>
  10. 10. Single-lens reflex (SLR): Digital Cameras
  11. 11. Overhead/Stationary: Digital Cameras <ul><li>High-volume reproduction </li></ul><ul><li>High-quality reproduction </li></ul><ul><li>Single angle of view </li></ul><ul><li>Expensive </li></ul><ul><li>Programmatic </li></ul><ul><ul><li>Mostly used for two dimensional art and books </li></ul></ul>
  12. 12. “ Scan-back” : Digital Cameras <ul><li>Scanning sensor usually replaces film in large-format view camera </li></ul><ul><ul><li>Scanning backs use a CCD sensor with a single row of pixels (sensing elements) that physically moves (scanned) across the image area, capturing one row of information at a time </li></ul></ul><ul><li>Extremely high resolution and quality </li></ul><ul><li>Long capture time </li></ul><ul><li>Requires high-end optics, dedicated computer </li></ul><ul><li>$20,000+ </li></ul>
  13. 13. Choosing a Digital Camera <ul><li>Most camera packages are not designed (primarily) for photographing objects </li></ul><ul><ul><li>Standard lenses for “landscape” or people </li></ul></ul><ul><ul><li>May need to purchase a special lens, e.g., macro, to capture object detail </li></ul></ul><ul><li>Manual exposure controls are essential </li></ul><ul><ul><li>Automatic exposure will make white or black background grey </li></ul></ul>
  14. 14. Choosing a Digital Camera <ul><li>Best if the camera can be “tethered” to a computer to allow live viewing of subject </li></ul><ul><li>Resolution is important, but only if the lens is of adequate quality and the camera is reasonably easy to use </li></ul><ul><li>Any digital SLR camera will meet requirements, a carefully chosen high-end P&S may suffice </li></ul>
  15. 15. Digital Camera Basics: Resolution <ul><li>DPI – dots per inch </li></ul><ul><ul><li>The measurement of resolution of display, printing, and capture systems. As the “dot” (or pixel) rate doubles, the number of dots quadruples. </li></ul></ul><ul><li>100 dpi = 100 x 100 = 10,000 dots/pixels per inch </li></ul><ul><li>200 dpi = 200 x 200 = 40,000 dots/pixels per inch </li></ul>
  16. 16. Digital Camera Basics: Resolution <ul><ul><ul><li>A 5 x 7 inch photograph captured at 600 DPI will be how many pixels across on its longest edge? </li></ul></ul></ul>
  17. 17. Digital Camera Basics: Resolution <ul><li>ANSWER: </li></ul><ul><ul><li>7 inches x 600 = 4200 dpi on the longest edge </li></ul></ul><ul><li>8 x 10 inches at 300 dpi is the same as: </li></ul><ul><ul><li>4 x 5 inches at 600 dpi </li></ul></ul><ul><ul><li>32 x 40 inches at 75 dpi </li></ul></ul>
  18. 18. Digital Camera Basics: Resolution <ul><li>Different output devices require different resolution </li></ul><ul><ul><li>Computer screens display at 72 dpi, although software may zoom in </li></ul></ul><ul><ul><li>Print devices print no higher than 300 dpi </li></ul></ul><ul><ul><ul><li>Human eye cannot discern more than 300 dpi without magnifier </li></ul></ul></ul><ul><li>For digital preservation higher resolution is better </li></ul><ul><ul><li>What sort of detail will a researcher need? </li></ul></ul><ul><ul><li>What will future technologies be able to display? </li></ul></ul>
  19. 19. Digital Camera Basics: Resolution <ul><li>Confusing terminology! </li></ul><ul><ul><li>Many printers offer high dpi, e.g., 1440 dpi </li></ul></ul><ul><ul><ul><li>Refers to the microscopic pixels that make up the printing dots that are at 300 dpi or less </li></ul></ul></ul><ul><ul><ul><li>A printer with higher dpi offers more gradations of color , rather than higher resolution. </li></ul></ul></ul>
  20. 20. Digital Camera Basics: Resolution and Megapixels <ul><li>Megapixels </li></ul><ul><li>The n umber of pixels that comprise the surface of the image sensor </li></ul><ul><li>1 megapixel = 1 million pixels </li></ul><ul><li>A 4.0 megapixel (or higher) can output an acceptable 8 x 10 inch printed image </li></ul><ul><ul><li>4 MP cameras have 2,289 x 1,712 pixels </li></ul></ul><ul><ul><ul><li>200 DPI image is 11.4” x 8.6” </li></ul></ul></ul><ul><ul><li>14 MP cameras have 4,500 x 3112 pixels . </li></ul></ul>
  21. 21. Digital Camera Basics: Resolution and Megapixels <ul><li>Megapixels do not equal quality! </li></ul><ul><ul><li>Camera manufacturers have greatly increased megapixel resolution, but noise has increased as well </li></ul></ul><ul><li>Physically larger sensors have less noise </li></ul><ul><ul><li>Digital SLR cameras offer noticeably better images compared to P&S cameras with higher numbers of pixels because P&Ss tend to be physically smaller cameras </li></ul></ul>
  22. 22. Digital Camera Basics: File Formats <ul><li>Digital images can be encoded in many ways </li></ul><ul><li>Most digital cameras record JPEG by default </li></ul><ul><ul><li>Lossy compression </li></ul></ul><ul><li>RAW format recorded from the sensor offers the most color and brightness detail </li></ul><ul><ul><li>However, each camera manufacturer has a different standard </li></ul></ul><ul><li>Some cameras can record TIFF files, which is the archival standard </li></ul><ul><ul><li>Recommended </li></ul></ul>
  23. 23. Digital Camera Basics: Capture <ul><li>Basic photography concepts </li></ul><ul><ul><li>Aperture </li></ul></ul><ul><ul><li>Shutter speed </li></ul></ul><ul><ul><li>White balance </li></ul></ul><ul><ul><li>Lighting conditions (Exposure) </li></ul></ul><ul><ul><li>Bracketing </li></ul></ul><ul><li>Other considerations </li></ul><ul><ul><li>Background </li></ul></ul><ul><ul><li>2d objects </li></ul></ul><ul><ul><li>3d objects </li></ul></ul>
  24. 24. Digital Camera Basics: Capture <ul><li>Aperture The size to which the shutter opens to let light in to the sensors </li></ul><ul><ul><li>The smaller the f-stop number, the larger the opening </li></ul></ul><ul><ul><li>The larger the f-stop number the greater the depth of field, or perception of distance </li></ul></ul><ul><ul><li>Similar to squinting </li></ul></ul>
  25. 25. Digital Camera Basics: Capture <ul><li>Aperture (slide 2) </li></ul>f/32 f/# 0.5 0.7 1.0 1.4 2 2.8 4 5.6 8 11 16 22 32 45 64 90 128 f/5 For f/32 or smaller (number wise) or larger (apeture wise) -- you’ll need a tripod because the lens will be open for a good long time.
  26. 26. Digital Camera Basics: Capture <ul><li>Shutter speed The amount of time the shutter is open, allowing light to be exposed to the sensors </li></ul><ul><ul><li>A fast shutter speed “freezes” movement </li></ul></ul><ul><ul><li>A slow shutter speed shows, or “blurs” movement </li></ul></ul><ul><ul><li>Measured in (parts of) seconds, e.g., 1/500 </li></ul></ul><ul><ul><li>Indoor settings: somewhere around </li></ul></ul><ul><ul><li>1/100 or 1/200 (you’ll need a tripod for </li></ul></ul><ul><ul><li>anything slower than 1/60 or so) </li></ul></ul>
  27. 27. Digital Camera Basics: Capture <ul><li>White balance In a camera, a setting that compensates for the differences in color temperature of the surrounding light. </li></ul><ul><ul><li>White balance adjusts the image’s colors to look similar to daylight </li></ul></ul><ul><ul><li>You can set custom white balance using a “white card” </li></ul></ul>
  28. 28. Digital Camera Basics: Capture <ul><li>White balance (continued) Indoor lighting is very different from natural lighting </li></ul><ul><ul><li>Incandescent lights (light bulbs) are yellow-red compared to sunlight </li></ul></ul><ul><ul><li>Fluorescents tend to look green </li></ul></ul><ul><li>P&S will try to make the background and the subject an even grey color </li></ul>
  29. 29. Digital Camera Basics: Capture <ul><li>Lighting conditions Aperture and Shutter Speed are determined by the availability and source of lighting </li></ul><ul><ul><li>Bright, sunny or hazy light allows for smaller apertures and faster shutter speeds: f/16, 1/500 </li></ul></ul><ul><ul><li>Overcast, close-up, back-lit subjects: f/5.6, 1/500 </li></ul></ul>
  30. 30. Digital Camera Basics: Capture <ul><li>Exposure The amount of light falling on the sensor </li></ul><ul><ul><li>Proper exposure is critical for image quality </li></ul></ul><ul><ul><li>Determined by: </li></ul></ul><ul><ul><ul><li>Brightness of the scene </li></ul></ul></ul><ul><ul><ul><li>Quality of the sensor </li></ul></ul></ul><ul><ul><ul><li>Shutter speed (ISO) </li></ul></ul></ul><ul><ul><ul><li>Aperture </li></ul></ul></ul>
  31. 31. Digital Camera Basics: Capture <ul><li>Bracketing </li></ul><ul><ul><li>Taking several shots of the same subject using different or the same camera settings </li></ul></ul><ul><ul><li>Typically used when lighting is challenging or there is lots of movement </li></ul></ul>125th/sec @ F8 – correct exposure 60th/sec @ F8 – overexposed 1 stop 250th/se @F8 – underexposed 1 stop
  32. 32. Digital Camera Basics: Capture <ul><li>Backgrounds </li></ul><ul><ul><li>Plain, non-reflective surface keeps focus on subject </li></ul></ul><ul><ul><li>Try several different colors or textures </li></ul></ul><ul><ul><ul><li>Neutral colors typically work best </li></ul></ul></ul><ul><ul><ul><li>Smooth out unnecessary folds </li></ul></ul></ul><ul><ul><ul><li>Cloth, table surface, foam core, etc. </li></ul></ul></ul>
  33. 33. Digital Camera Basics: Capture <ul><ul><li>Papers, maps, and photos (“flat” material) </li></ul></ul><ul><ul><li>Soft, even light across entire surface. No glares or light spots </li></ul></ul><ul><li>Two-dimensional objects </li></ul>
  34. 34. Digital Camera Basics: Capture <ul><ul><li>Avoid keystoning, or distortion: photograph from a central point directly above (if laid horizontally) or parallel (if vertically) </li></ul></ul><ul><ul><li>Resolution: sufficient that the digital surrogate can be reproduced at the same or larger size as original </li></ul></ul><ul><li>Two-dimensional objects </li></ul>
  35. 35. Digital Camera Basics: Capture <ul><li>Three-dimensional objects </li></ul><ul><ul><li>Household items, sculpture, clothing, tools </li></ul></ul><ul><ul><li>Avoid light spots or extreme shadows </li></ul></ul><ul><ul><li>Get close </li></ul></ul><ul><ul><li>Consider taking more than one photograph (e.g., full & detail) </li></ul></ul><ul><ul><li>Shoot in the shade or on a cloudy day to take advantage of soft lighting and to show more detail </li></ul></ul><ul><ul><li>Expect to experiment, and that means time! </li></ul></ul>
  36. 36. Digital Camera Basics: Environment <ul><li>Camera. Check. What else do you need? </li></ul><ul><ul><li>Lights </li></ul></ul><ul><ul><li>Physical space </li></ul></ul><ul><ul><li>Accessories </li></ul></ul><ul><ul><ul><li>Ladder, table, tripod </li></ul></ul></ul><ul><ul><ul><li>Gloves, object stands </li></ul></ul></ul><ul><ul><ul><li>Computer storage – or direct computer connection </li></ul></ul></ul><ul><ul><ul><li>Others? </li></ul></ul></ul>
  37. 37. Digital Camera Basics: Environment <ul><li>Physical space recommendations </li></ul><ul><ul><li>Dedicated </li></ul></ul><ul><ul><li>Appropriate and adequate lighting </li></ul></ul><ul><ul><li>Adequate physical space to capture your objects </li></ul></ul><ul><ul><ul><li>A large object will require a greater amount of space for capture </li></ul></ul></ul><ul><ul><li>Quiet and clean </li></ul></ul><ul><ul><li>Ideally, the walls and floors are neutral colors and low reflection </li></ul></ul><ul><ul><li>Storage for accessories when not in use </li></ul></ul>
  38. 38. Digital Camera Basics: Costs <ul><li>Digital Camera </li></ul><ul><ul><ul><li>10 Megapixel P&S => $300 </li></ul></ul></ul><ul><ul><ul><li>10 Megapixel SLR => $900 </li></ul></ul></ul><ul><ul><ul><li>Scan-back systems => $25,000+ </li></ul></ul></ul><ul><li>Lenses </li></ul><ul><ul><ul><li>$100+ </li></ul></ul></ul><ul><li>Lights </li></ul><ul><ul><ul><li>2-light “economy” kits start at $150 </li></ul></ul></ul><ul><li>Tripod </li></ul><ul><ul><ul><li>$25-$300 </li></ul></ul></ul>
  39. 39. Digital Camera Basics: Costs <ul><li>The top-rated 8 MP (and up) semi-pro SLR cameras reviewed by CNET staff as of 10/8/2007 were </li></ul><ul><li>Nikon’s D200 and </li></ul><ul><li>Canon’s EOS 20D. </li></ul><ul><li>They cost between $800 and $2000. </li></ul>