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Digital Cameras


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Digital Cameras

  1. 1. DigitalCameras<br />
  2. 2. Digital Camera Types<br />2<br />Prosumer*<br />Mobile Phone <br />Professional SLR<br /><ul><li>Expansive
  3. 3. Versatile
  4. 4. Better images
  5. 5. Responsive
  6. 6. Bulky
  7. 7. Heavy
  8. 8. Cheap
  9. 9. Small
  10. 10. Light</li></ul>Point & Shoot<br />Prosumer SLR<br />*Prosumer = Consumer cameras with some pro-like capabilities<br />
  11. 11. Digital Camera Operation<br />3<br />Camera Body<br />1) The lens focuses light reflected from the subject onto the sensor<br />2) Pressing the shutter button opens the shutter briefly to allow light in<br />3) The image sensor converts the light into electric signals<br />Shutter<br />Light<br />ImageSensor<br />Subject<br />DigitalImageProcessor<br />Lens<br />5) The image file is stored in the memory card<br />4) The digital image processor transforms the signals into an image file (usually in jpeg format)<br />MemoryCard<br />
  12. 12. SLR vs. Fixed-Lens Cameras<br />4<br />
  13. 13. The Lens - Zoom<br />5<br />Changing the distance between the elements magnifies/shrinks the image (zoom in & out) <br />Camera lenses are made up of glass elements<br />Zoom range (AKA focal range) is measured in millimeters in image magnification factor (xN)<br />Fully-extended lens<br />Example: x31 zoom from 18mm (wide) to 250mm (tele) <br />
  14. 14. The Lens - Aperture<br />6<br />Light enters the lens through the aperture hole which can be made bigger or smaller to allow more or less light in <br />Aperture size is measured in f-numbers or stops<br />f/1.4<br />f/16<br />Lenses indicate their maximal aperture in wide and full-tele modes (smaller numbers are better)<br />A lens capable of big apertures (small f-numbers) isbetter: allows more light in in low-light conditions and enables shallow depth-of field images<br />f/32<br />f/5.6 (shallow depth of field)<br />
  15. 15. What to Look For in a Lens<br />Zoom range<br />Wide for scenery shots<br />Zoom for portraits, sports, wildlife <br />Big apertures (low f-numbers)<br />Allow in more light and shallower depth of field<br />Sharpness<br />In center and in corners<br />Minimal distortion<br />Especially in wide and in full-tele<br />Materials and build quality<br />Glass materials, coating, body materials<br />7<br />
  16. 16. Image Sensor – Resolution and Size<br /><ul><li>Image sensors affect image quality and resolution (how many dots, or pixels make up the picture) </li></ul>Resolution is mainly important when printing pictures <br />8MP (megapixel) is sufficient for most print sizes <br />More resolution ≠ Better images<br />Sensors come in a variety of sizes<br />Usually the bigger the camera the larger the sensor <br />Bigger sensor  better image quality<br />8<br />
  17. 17. Image Sensor – Noise<br />Sensors generate random variation in brightness or color, called Image Noise<br />Image noise depends on:<br />Sensor quality<br />Sensor size – smaller sensors are noisier <br />Cameras have built-in Noise-Reduction (NR),but this reduces detail<br />9<br />Noise-free image<br />Noisy image<br />
  18. 18. Image Stabilization (IS)<br />Image stabilization (IS), is an electro-mechanical system built into a camera or a lens <br />Reduces camera shake and thus image blur<br />Also known as Vibration Reductions (VR) <br />10<br />Example: IS implemented by moving lens elements to counteract camera motion<br />
  19. 19. ISO (Sensitivity)<br />ISO= light sensitivity – the ability to capture images in low-light<br />Measured in ISO values: 64, 100, 200, 400, 800, 1600, 3200…<br />Higher numbers indicate higher sensitivity <br />Cameras allow increasing ISO level to capture images in low-light conditions<br />Theoretically the higher the ISO the camera enables the better<br />However higher ISO = higher image noise<br />Depends on sensor quality and size<br />Most digital cameras produce unusable images with highest ISO levels<br />11<br />ISO 400<br />ISO 1600<br />
  20. 20. LCD Screen<br />Things to look for:<br />Screen Resolution<br />Higher resolution = more details <br />Visibility in strong day light <br />Swivel / Tilt<br />Enables shooting from different angels<br />12<br /><ul><li>The LCD screen at the back of the camera is used to control it and to review images and movies</li></ul>Swivel-and-Tilt Screen<br />
  21. 21. Camera Features<br />Manual Controls - allow controlling all picture-taking parameters – aperture, shutter speed, ISO<br />13<br /><ul><li>Face Detection – the camera automatically focuses on the faces in the image
  22. 22. Live Histogram – the histogram shows light distribution in the image, thus indicating whether the image is well-exposed . </li></li></ul><li>Summary - Things to Consider<br />14<br />
  23. 23. Photo Credits<br />Night Time is the Right Time / Jakob Montrasio,<br />15<br />
  24. 24. Legal Note<br />This presentation is provided for use under the terms of Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 license.<br />(You may use, distribute, embed and make copies. You may not make commercial use or change. Attribution to the creators is required)<br />16<br />