Aperture: the opening in the camera lens that controls the amount of light the enters controlled by very thin blades that over lap
Depth of Field: the portion of scene in a photograph that is in clear sharpfocus. It is controlled by 3 factors:
1. F-Stop - This is primarily controlled by the camera lens' F-Stop or Aperture.
The higher the F-Stop(f8, f11, f16 small opening) the more depth of field (more in focus) the photo will have.
The lower the F-Stop (f2, f2.8, f4 bigger opening) the LESS depth of field.
2. Distance -
The closer the camera is to the subject the LESS depth of field it will have.
3. Lens Type - The more telephotoa lens is the less depth of field it will have.
F-Stop: The numerical value given to the opening (or aperture) in the camera lens that controls the amount of light the enters.
Telephoto: Telephoto lenses compress or squish the subject more causing a blurrier background.
Sunny F16 Rule: In you are shooting in bright sunlight your exposure can be set by setting your lens on F16 and setting your shutter speed to match the number closest to your film speed (if using 400 ISO film your fstop woud be f/16 and the shutter would be 1/500. If using 100 ISO film speed the Fstop is f16 and the shutter would be 1/125).
120 FIlm: This type of film, commonly called medium format,(seen below on the left) is almost twice the size of 35mm film format seen on the right..