Photo Notes. Lesson 2.

Understanding the focus.
- 1. Subject.
- 2. Light reflecting from the subject.
- 3. Lens correctly focused.
- 4. Light refracted by lens onto sensor.

Shutter speed.
How fast the shutter opens and closes to let light into the camera.
1/250th of a second is fast. You use it in light conditions.
1/30th of a second is slow. You use it for in dark conditions. 

Aperture.
How big the opening of the lens is to let light in.
f/2.1 is a large opening of the lens.
f/22 is a small opening of the lens.
 Higher the F number is the larger the dept of field is.

The smaller number there is the bigger the hole gets.