1. Introduction to Digital Photographyby
Edmund H. Smith, Jr.
March 2009

2. Discussion Items Photography Basics
Differences between 35mm and digital camera lenses
How digital image sensors work
File formats – RAW, TIFF, JPEG
EXIF data and how to get to it
Adding GPS positional data to a photo
Placing shooting data on a photo

3. Pinhole Camera

4. Photographic Film as an Image Sensor
Film sensitivity is defined by it’s ASA rating…now called ISO

5. Field of View Image Sensor Angular Field Of View Image Sensor Size
Focal Length

6. 1200 feet Altitude (AGL) 800 foot deep by 800 foot wide photo image
Camera
Field of
View
45 degree
Camera
Angle
1200 feet
Altitude (AGL)
800 foot deep by 800 foot wide
photo image
0.2 minutes
of latitude

7. Changing the Field of View
Wide-Angle
Telephoto
Mid-Range

8. Examples 40 degree field of view 80 degree field of view
Assume Image Sensor Width of 35 millimeters
40 degree field of view
50 millimeter focal length
80 degree field of view
28 millimeter focal length
20 degree field of view
105 millimeter focal length

9. But We Need More Light!
A Larger Pinhole Will Not Work!

10. Gathering More Light With a Lens

11. Selecting Field of View by Changing Lens Focal Length

12. Adjusting Exposure by Changing Aperture
F Stop
small aperture = large F number, i.e. F 22
large aperture = small F number, i.e. F 2.8

13. One Can Adjust Exposure by Changing the Shutter Speed

14. Digital Camera Sensor Sizes

15. Impact of Changing Image Sensor Size

16. Digital Camera Example
Olympus SP-570UZ
Image sensor (Charge Coupled Device)
6.36 x 4.24 mm
Lens focal length
4.6 to 92 mm (analog zoom range)
35 mm equivalent – 26 to 520 mm!
Aperture
F 2.8 to F 8.0
Shutter Speed
15 seconds to 1/2000 seconds

17. Digital Image Sensor Two Types Charge Coupled Device (CCD)
Complimentary Metal Oxide Semiconductor (CMOS)

18. Digital Image Sensor Analog to Digital Converter Light
eeee
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Light
Number of pixels defines sensor resolution
i.e. – 10 megapixel sensor has 10 million pixels

19. What About Color?

20. Primary Colors
RGB – Red, Green and Blue

21. How Does A Digital Image Sensor Measure Color?
Each pixel measures light intensity for one of three colors
Interpolation from nearby pixels determines true color for each pixel

22. RAW Image Data Digital Data for each pixel
RAW is not a standard; format varies with specific sensor and camera manufacturer
RAW data is unprocessed
RAW data files can be very large!

23. TIFF Tagged Image File Format
A standard
Widely used by publishing industry
TIFF processes RAW data for white balance, color saturation, contrast, sharpness, etc.
File size may be smaller than RAW
8 bits per pixel verses 10 bits or more for RAW

24. JPEG Joint Photographic Experts Group (JPEG)
A standard
A image file compression format
Typical 10/1 file size reduction
Trade off between file size and picture quality
JPEG Course
JPEG Normal
JPEG Fine
Widely used by amateur and professional photographers

25. Image Redundancy

26. Two Types of Internal Camera Processing

27. Exchangeable Image File -also referred to as an EXIF Metafile-
EXIF is a Standard
EXIF JPEG
EXIF TIFF
Defines how shooting data is imbedded in the image data file
Camera make and model
Date and time of image capture
F-stop, shutter speed, white balance, lens focal length., longitude and latitude, …..
You can get access to the EXIF Data

28. Camera Software May Include EXIF Viewer

30. Nikon Picture Project Software

31. EXIF Data From Nikon Picture Project
Color Mode: Mode I (sRGB)
Tone Comp.: Auto
Hue Adjustment: 0°
Saturation: Auto
Sharpening: Auto
Image Comment:
Long Exposure NR: Off
Latitude: N 26°55.02'(26°55'1.2")
Longitude: W 82°0.94'(82°0'56.4")
Altitude: m
High ISO NR: On (Normal)

32. Down-loadable EXIF Reader
Tip! Google “EXIF Reader”

33. How do I add GPS position to my photographs?
Google - GPS Data Logger/Photo Tracker

34. How do I put shooting data on my photograph?
0r Google “Timetophoto”

36. Summary
Digital camera lens focal lengths are different than 35 mm cameras lenses because the image sensors are of different sizes.
Digital SLR cameras can use lenses designed for 35 mm film cameras.
RAW data files are just that; unprocessed RAW data.
JPEG is the file format of choice for digital amateur photographers – it’s a standard!
Shooting data is embedded in the JPEG image file. The user can get access to it!
It is easy and inexpensive to add GPS position data to your photography.
It is easy and inexpensive to put shooting data on the photograph itself.

37. Edmund H. Smith, Jr. smith5439@comcast.net 941 575 2026 865 408 3102
March 2009