1. Lenses Are classified by their Focal Length

2. The distance from the optical center of a lens to the front surface of the imaging device.

3. Short Focal Length Wide Angle View

4. Short Focal Length EXAMPLE Entire Football Team

5. Long Focal Length Narrow Angle View

6. Long Focal Length EXAMPLE One Football Player

7. Zoom Lens Variable Focal Length

8. Zoom Range How close to how far a lens can see

9. Lens Speed How much light can pass through a lens

10. Fast Lens Lets a great amount of light to pass through

11. Fast Lens Use in the evening, when there isn’t much light. For low light settings

12. Slow Lens Lets a small amount of light to pass through

13. Slow Lens Use this on bright, sunny days For bright light settings

14. Iris Adjustable lens opening mechanism

15. Aperture Hole in center of iris Measured by f-stops

16. Aperture Similar to the pupil of your eye

17. Aperture Can adjust larger or smaller depending on the amount of light

18. Aperture What type of aperture opening would you use for a sunny day?

19. Aperture What type of aperture opening would you use for a dark room with only a candle for light?

20. Auto Iris Many cameras have auto iris Adjusts automatically depending on setting

21. Focus When subject in viewfinder is sharp and clear.