1. Residential Security, Access Control, and Surveillance Copyright © 2005 Heathkit Company, Inc. All Rights Reserved Presentation 16 – The Camera Lens

2. 2 Objectives At the end of this presentation, you will be able to:

3. 3 Explain the difference between a CS and C mount. Explain the difference between a video and DC automatic iris. Explain how an automatic iris works.

4. 4 Define aperture, focal length, iris, depth of field, and f-number. State the general relationship between the focal length and the field of view of a typical lens. State the general relationship between the f-number and the maximum width of the iris opening.

5. 5 Lens Characteristics Mount Type Focal Length Maximum Aperture Size Motorized Controls

6. 6 Lens Mounts Standardized types C CS

7. 7 C Mount CS Mount

8. 8 17.5 mm C-Mount CCD

9. 9 12.5 mm CS-Mount CCD Back Lens Element

10. 10 12.5 mm CCD 5mm Spacer 17.5 mm

11. 11

12. 12 Focal Length Distance between the center of a lens and the camera’s sensor Shorter focal lengths display a wide area Longer focal lengths allow close-ups

13. 13 Focal Length Angle of View Type 1.6 mm110°Ultra-wide 2.8 mm80°Wide 4 mm60°Normal 12 mm20°Telephoto 50 mm5°Telephoto 100 mm4°Long Telephoto

14. 14 5°, 50 mm 30°, 16 mm 57°, 3 mm Lens CCD Sensor

15. 15

16. 16 Iris/Aperture Controls the amount of light that strikes the sensor Size is given by the f-number, or f-stop Smaller f-numbers mean larger apertures Larger f-numbers mean less light

17. 17

18. 18

19. 19 Over-exposed image Under-exposed image

20. 20 The Auto-Iris

21. 21

22. 22

23. 23 Light Sensor DC Voltage DC Drive

24. 24 Light Sensor Video Signal Video Drive

25. Residential Security, Access Control, and Surveillance Copyright © 2005 Heathkit Company, Inc. All Rights Reserved End