1. Lab 10: Lenses Focal Length Magnification Lens Equation Depth of Field
Spherical Aberrations and Curved Focal Plane
Chromatic Aberration
Astigmatism (Optional)
Barrel and Pin Cushion Distortion (Optional)
Diverging Lenses
Do experiment #5 after all other experiments

2. Lenses Lab Basic ideas on single lens distances quality of images
object, image and focal
quality of images
photography needs good images on the film
problems with single lens

3. Light Rays ? ? ? ? If there is only one light ray…
A light source could be anywhere along the dashed line
We sometimes oversimplify ray diagrams by showing only one ray of light and specify the image or source location. This slide challenges students on this concept.

4. Light Rays Diverging rays give perception of the source location
A key concept necessary to identify source location.
Diverging rays give perception of the source location

5. Optical Image Optical elements Diverging light rays
This slide extends the concept of source location to concept of image location.
Diverging light rays
 perception of apparent light source
Converging point
 image of light source

6. Light Rays Light rays from far away object appears to be...
Some students lack ideas on parallel rays. Where do they originate? How parallel are they? What kind of source generate them?

7. Parallel Rays Nearly parallel! Huh?
We don’t need to pretend that it is parallel. We could also compare with the astronomical distance scale and angles measurable with a protractor.
Nearly parallel! Huh?

8. Converging Lens F F parallel rays converge at F
focal length f
optical axis
parallel rays
focal points F F
There are too many texts in this slide if shown at once. We need to go through one by one.
parallel rays converge at F
each lens has a unique f

9. Ray Diagram tip of arrow parallel real image center through F Image
tip of arrow
parallel
real image
center
through F
It’s important to point out that this diagram only identifies the location of the tip of the arrow.
Image
(tip of arrow)

10. Image Quality  

11. Image Quality
Focused  
Sharp image

12. Image Quality
Slightly out of focus  
Smeared image

13. Image Quality
Out of focus  
No image

14. Magnification How much larger? 10 or 0.5? Object Image
Magnification: ratio of image size to object size

15. Light Unit Plastic ruler is on the light source! mm
Face view mm
The manual instructs students to use the plastic ruler to measure the source size. They immediately rush to a meterstick. I always laugh. Ha, ha, ha!
Plastic ruler is on the light source!
Inner circle diameter: 10 mm