1. Lens Applications & Technologies

2. airglass

3. airglass

4. air glass air

5. The Convex Lens as a Magnifier Object(s) Image(s)

6. Convex Lenses Used as Magnifiers Object(s) Image(s)  Upright  Larger  Virtual Virtual image Object F’ F Magnifying glass

7. The concave Lens as a De-Magnifier Object(s) Image(s)  Upright  Smaller  Virtual

8. Convex Lens is Inverse of Concave Lens

9. Refraction in Water Surface of water is like a collection of lenses which change shape.

10. Image Formation Without angle-selectivity, light from all parts of the object overlap all parts of the wall. A pinhole or a lens directs rays from one part of the object to only one point on the screen. In bright light, the eyes' pupils becomes smaller, allowing sharper images to form. wall Pinhole camera lens

11. Image Formation with Lenses If the object is far from the lens (beyond the focal point), a real, inverted image is formed.

12. Film Projectors Object is near F (but still between F & 2F) Image is:  very far away!  inverted  larger  real Projector: bulb Object (upside down) lens Screen Image

13. Camera Film Image (well beyond 2F!)  i nverted  smaller  real Image Object Film Lens (screen)

14. Spherical Aberration Rays away from the center are not focused at the focal point. See Figure 12.9 on page 492. Spherical aberration causes beams parallel to, but distant from, the lens axis to be focused in a slightly different place than beams close to the axis. This results in the blurring of the image.

15. Chromatic Aberration Different colors refract by different amounts. See Figure 12.9 on page 492.

16. Chromatic Aberration See Figure 12.9 on page 492. the dispersion of light through a lens spherical and chromatic aberration in thick lenses reduces the quality of images in cameras chromatic aberration of a lens is seen as fringes of colour around the image. can be partially corrected by combining lenses

17. Examples of Chromatic Aberration

18. Achromatic Lens Ideally, all colours are reconverged! However, with two lenses, usually only red and blue can be reconverged, leaving green unfocussed... Different types of glass Single focal point

19. Apochromatic Lens! THREE lenses – ALL colours are reconverged!

20. Microscope (compared to the object) Large (compared to the “object”) Object close to, but outside, F o The real image formed by the objective lens acts like the object for the eyepiece lens. Between Fe and the eyepiece!

21. Microscope 1. Rays from the specimen pass through the objective lens and the refracted rays form an inverted real image between the lenses. 2. Rays from the image pass through the eyepiece, which again refracts the rays, and then forms the final inverted, virtual image. i.e. The image produced by the objective lens in a microscope becomes the object for the eyepiece. See Figure 12.21 on page 505.

22. Microscope See Figure 12.21 on page 505.

23. Refracting Telescope Very tiny (compared to the object!) Virtual image of the real image Very large compared to the “object” (the real image) FoFo FeFe Just inside F e …

24. Reflecting Telescopes Newtonian Primary mirror Secondary mirror (concave)(plane) Primary mirror (concave) Secondary mirror(convex) Corrector plate (Schmidt Cassegraine) Cassegraine

25. Correcting Human Vision Using Lenses

28. Nearsighted Vision - myopia

29. Correcting Human Vision Using Lenses

30. Farsighted Vision- hyperopia

31. Homework Page 493 # 6 – 8 Page 505 # 1 – 3 Page 511 # 3 – 5, 8