Understanding f stops on the camera
For the f stops formula is this:
Large f-stop = Small opening
Small f-stop = Large opening
The larger number represents the lower end of the scale, less light entering the camera.
A smaller F-stop number means the opening is larger, more light entering the camera.
For a larger F-stop number requires a slower shutter speed. A smaller opening means less light is reaching the camera, so it needs more time to create a picture or exposure. A smaller F-stop number, requires a faster shutter speed. Less time is needed to create the exposure.
Slow shutter speed = larger F-stop number = less light being let in (smaller opening) = more in focus (larger depth of field). Depth of field means the sharp area surrounding the point of focus.
General Mode Settings on cameras:
Fully Manual – ( M Mode )
Usually denoted by an M on the exposure mode dial. You select both the aperture and shutter speed yourself to obtain the exposure you are going after.
Aperture Priority – ( A Mode )
Usually denoted by an A or Av on the exposure mode dial. You select the aperture while the camera sets the shutter speed.
Shutter Priority – (S Mode )
Usually denoted by an S or Sv on the exposure mode dial. You select the shutter speed while the camera sets the aperture.
Common f stop ranges
f-stops are determined by diameter. The progression of f-stops are; 1 – 1.4 – 2 – 2.8 – 4 – 5.6 – 8 – 11 – 16 – 22 – 32.
Read this article at photoNur website: http://www.photonur.com/fstops.htm