1. Light, Lens, & Zoom
Digital Photography
Apollo Technology Education

2. Visible Light
Visible light waves are the only electromagnetic waves we can see.
We see these waves as the colors of the rainbow. Each color has a different wavelength.
Red has the longest wavelength and violet has the shortest wavelength.
When all the waves are seen together, they make white light.

3. Prisms: Seperating the Colors
When white light shines through a prism, the white light is broken apart into the colors of the visible light spectrum. Water vapor in the atmosphere can also break apart wavelengths creating a rainbow.
Light changes speed when it enters a different medium (air – glass – water vapor, etc.); the result is a refraction of light.
Prism: breaks white light into the colors of the visible light spectrum

4. Check out that Reflection….
The Sun is a natural source for visible light waves and our eyes see the reflection of this sunlight off the objects around us.
The color of an object that we see is the color of light reflected. All other colors are absorbed.
The human eye and the camera process light in very similar fashion.
We see reflections of subjects.

5. The Human Eye

6. Camera
Definition: a device that consists of a lightproof chamber with an aperture fitted with a lens and a shutter through which the image of an object is projected onto a surface for recording (as on film) or for translation into electrical impulses (as for digital cameras)

7. The Camera

8. Lens
Definition: a ground piece of glass used to gather and focus light. Can be singular or a series of lenses.
Focal Length: The distance from the point where light enters a lens and where an image is focused.
Note: focal length measured in mm (millimeters)

9. Optical Zoom
Definition: A series of lenses that changes the focal length to magnify the image.
“Good Zoom”
If possible, move the camera in closer…. “Redneck zoom”
Observe how the projection plane at the left receives light on the opposite side it entered the lens. Image is “flipped”.
Light is focused on the projection plane (digital light-sensitive chip or film located here) to form image.

10. Lens Cutaway

11. Lens Cutaway
Note: point out multitude of lenses, location aperture, and sensor/chip

12. Digital Zoom
Definition: The camera takes pixels from the center of the image sensor and stretches them or “interpolates” them to make an enlarged image.
“Bad Zoom”
Avoid it!
Turn it off!
“Bad Zoom”
Similar to zooming in on a computer screen
Pixelation
OK for basic documentation work, but not recommended for quality images

13. Optical vs. Digital Zoom

14. Don’t be Fooled!