color physics behind the lens, mean to say about color optics of camera ,heading from components to optics , color physics behind the lens

1. Presentations
@IIT-D
BY
VIVEK YADAV
9457631264

2. A Presentation On Color Physics In Digital
Camera
Submitted by-
Vivek Yadav
Submitted to
Dr. S. Mukhopadhyay

3. DSLR OPTICS

4. DSLR CAMERA
DIGITAL SINGLE LENS REFLEX

5. PINHOLE CAMERAS
FOCAL LENGTHF
S
E
N
S
O
R S
I
Z
E
S
FILM/SENSOR
IMAGE
PINHOLE APPERTURE
SCENE
 EACH POINT IS ILLUMINATED OR REPRESENTED FROM A SINGLE
DIRECTION.
 SIMPLEST AND EASIEST FORM OF CAMERA

6. SMALL APERTURE VS BIG APERTURE

7. SOLUTION IS USE OF LENS

8. WHERE IS IMAGE FORMED/ LENS OPTICS
 CHANGE IN FOCAL LENGTH CHANGES THE PERSPECTIVE
OF VIEWING, IF AN OBJECT IS PLACED AT A DISTANCE D’
D’
F
D

9. FIELD OF VIEW
 F ALSO DEFINES THE FIELD OF VIEW FOR A DEFINITE
SIZE OF SENSOR.
 DOUBLE THE FOCAL LENGTH, HALF THE FIELD OF
VIEW.
 SHORTER THE F, WIDER THE VIEW.
2F

10. EXPOSURE
UNDER
EXPOSED
OVER
EXPOSED
RIGHT
EXPOSED
• ANY PHOTOGRAPH STARTS AS A BLANK CANVAS, SO HOW
YOU CHOOSE TO APPLY LIGHT TO IT DETERMINES THE VISUAL
ATTRIBUTES OF A PHOTOGRAPH
• INTENSITY OF LIGHT TO THE SENSOR
PARAMETERS INVOLVED ARE :
1. SHUTTER SPEED
2. APERTURE AREA

11. SHUTTER SPEED
 HOW LONG LIGHT IS TO BE STROKED ON SENSORS.
 MEASURED IN A FRACTION OF A SECOND.
 E.G. 1/30, 1/60, 1/125, 1/250, 1/500
FAST SHUTTER SPEEDS IS USED IN SPORTS
PHOTOGRAPHY BUT THEY CAPTURE LESSER AMOUNT OF
LIGHT.
SLOW
SHUTT
ER
SPEED
FAST
SHUTT
ER
SPEED

12. APERTURE
 DIAMETER OF LENS OPENING.
 EXPRESSED AS FRACTION OF FOCAL LENGTH CALLED
F-NUMBER
 E.G. F/2 ON 5`0MM LENS = 25 MM APERTURE
 BIGER F NUMBER MEANS SMALL APERTURE
 LARGE APERTURE MEANS MORE LIGHT BUT
SHALLOW DEPTH OF FIELD (BOKEH EFFECT)

13. SMALL APERTURE
LARGE DEPTH OF FIELD
LARGE APERTURE
SHALLOW DEPTH OF FIELD

14. HOW TO CORRELATE THE TWO ?
 EXPOSURE = SHUTTER SPEED
F-NUMNBER2

15. ISO SCALE/GAIN LEVEL
 ISO SCALE INDICATES SENSOR SENSITIVITY TO LIGHT:
 ISO 100 - LOW SENSITIVITY, GOOD FOR BRIGHT
CONDITIONS,
 STATIC SCENES, WIDE APERTURE, SLOW SHUTTER
 ISO 1600 - HIGH SENSITIVITY, GOOD FOR LOW
LIGHT,
 DYNAMIC SCENES, SMALL APERTURE, FAST SHUTTER

16. CAMERA MODES
 PROGRAM MODE (P) - CAMERA INTELLIGENTLY
CHOOSES SHUTTER SPEED AND APERTURE TO
ACHIEVE CORRECT EXPOSURE
 SHUTTER PRIORITY (S) - USER SETS SHUTTER SPEED,
CAMERA CHOOSES APPROPRIATE APERTURE
 APERTURE PRIORITY (A) - USER SETS APERTURE,
CAMERA CHOOSES APPROPRIATE SHUTTER SPEED
 MANUAL MODE (M) - USER SETS BOTH APERTURE AND
SHUTTER SPEED

17. Basic colour physics in camera …..

18. GENERAL DIGITAL CAMERA
WORKFLOW

19. WHAT HAPPENS JUST AFTER SHUTTER

20. How to capture colors ?
 Beam splitter ?
 Spinning Disk ?
Pros & cons ?
 Bayer filter ?
Pros-
 Only one sensor
 Same time information recorder
 Foveon Type Sensor?

21. WHAT HAPPENS WITH FILM? NO SENSOR…
WHAT WE USE ? SILVER HALIDE ….MECHANISM ?

22. DIGITAL CAMERA SENSORS
CCD= Charge Coupled Device
CMOS= Complementary Metal Oxide Semiconductor

23. BASIC MATERIAL ; SILICON DIODE
HOW IT WORKS ?
REVERSE BIASED ?

24. CCD SENSORS

25. CCD SENSOR WORKING

26. CMOS SENSOR

27. BASIC DIFFERENCE
1. ELECTRICITY CONSUMPTION?
100 times more ?
2. SOUND LEVEL ?
3. DATA CAPTURING ?
BASIC DIFFERENCE IN A VIEW

28. CCD CMOS
 The charge is actually transported
across the chip and read at one corner
of the array.
 CCDS transport charges without
distortion.
 CCD sensors, as mentioned above,
create high-quality, low-noise images
 There are several transistors at each
pixel that amplify and move the charge
using more traditional wires. The
CMOS approach is more flexible
because each pixel can be read
individually.
 CMOS sensors traditionally consume
little power. Implementing a sensor in
CMOS yields a low-power sensor.
 CMOS sensor has several transistors
located next to it, the light sensitivity
of a CMOS chip is lower. Many of the
photons hitting the chip hit the
transistors instead of the photodiode.
Differences at a glance

29. HOW THE COLOR DATA STORED ?

30. REFERENCES
 Jim White and Tony Sweet(eds.), Nikon DSLR The Ultimate
Photographer’s Guide, Canada, Elsevier Ltd., 2010.
 Christopher Grey(ED.), CANON DSLR The Ultimate Photographer’s
Guide, Canada, Elsevier Ltd., 2008,
 Efficient Smart CMOS Camera Based on FPGAs Oriented to Embedded
Image Processing Ignacio Bravo *, Javier Baliñas, Alfredo Gardel, José
L. Lázaro, Felipe Espinosa and Jorge García
 Digital photography by Dennis P. Curtin
 Digital photography technique by J.A. KING
 Other study materials have been attached to mail ……