13. Digital Camera Operation 5 Camera Body 1) The lens focuses light reflected from the subject onto the sensor 2) Pressing the shutter button opens the shutter briefly to allow light in 3) The image sensor converts the light into electric signals Shutter Lens Light ImageSensor Subject DigitalImageProcessor 5) The image file is stored in the memory card 4) The digital image processor transforms the signals into an image file (usually in jpeg format) MemoryCard
14. The Lens - Zoom 6 Changing the distance between the elements magnifies/shrinks the image (zoom in & out) Camera lenses are made up of glass elements Zoom range (AKA focal range) is measured in millimeters or in image magnification factor (xN) Fully-extended lens Example: x31 zoom from 18mm (wide) to 250mm (tele)
15. The Lens - Aperture 7 Light enters the lens through the aperture hole which can be made bigger or smaller to allow more or less light in Aperture size is measured in f-numbers or stops f/1.4 f/16 Lenses indicate maximal aperture in wide and full-tele modes (smaller numbers are better) 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 f/32 f/5.6 (shallow depth of field)
16. What to Look For in a Lens Zoom range Wide for scenery shots Zoom for portraits, sports, wildlife Big apertures (low f-numbers) Allow in more light and shallower depth of field Sharpness In center and in corners Minimal distortion Especially in wide and in full-tele Materials and build quality Glass materials, coating, body materials 8
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18. Image Sensor – Noise Sensors generate random variation in brightness or color, called Image Noise Image noise depends on: Sensor quality Sensor size – smaller sensors are noisier Cameras have built-in Noise-Reduction (NR),but this reduces detail 10 Noise-free image Noisy image
19. Image Stabilization (IS) Image stabilization (IS), is an electro-mechanical system built into a camera or a lens Reduces camera shake and thus image blur Also known as Vibration Reductions (VR) 11 Example: IS implemented by moving lens elements to counteract camera motion
20. ISO (Sensitivity) ISO= light sensitivity – the ability to capture images in low-light Measured in ISO values: 64, 100, 200, 400, 800, 1600, 3200… Higher numbers indicate higher sensitivity Cameras allow increasing ISO level to capture images in low-light conditions Theoretically the higher the ISO the camera enables the better However higher ISO = higher image noise Depends on sensor quality and size Most digital cameras produce unusable images with highest ISO levels 12 ISO 400 ISO 1600
25. Photo Credits Night Time is the Right Time / Jakob Montrasio, http://www.flickr.com/photos/yakobusan/280627593/ 17
26. Legal Note This presentation is provided for use under the terms of Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 license. (You may use, distribute, embed and make copies. You may not make commercial use or change. Attribution to the creators is required) 18
