Digital Photography - Manual Control

Manual camera control simply means you, the user, must make the majority of the exposure decisions.

When you set the camera into Manual Mode you must tell the camera through control settings how you want to expose the subject.

The camera will automatically make light measurements through its internal light meter, and this is dependent on the exposure points shown in the viewfinder. Based upon what the camera measures you will have to set the following:

ISO values (Sensitivity to light) (100, 200, 400, 800, 1600, etc.)
Shutter Speed (How fast the image is captured. (bulb (open until you release the shutter button), 1/30sec, 1/60sec. 1/120sec., 1/250sec., 1/500sec., 1/1000sec.).
Aperture Setting (the opening through the lens that allows light to strike the photo sensitive element. ( f/2.0, f/2.4, f/4.5, f/8.0, f/11.0, f/16, f/22, f/32, etc.)
Focus on the primary subject.
Depth of Field (from the primary subject, in front of the subject, and behind the subject.)
Hyper-Focal Range (adjusting the lens focus range to include all important aspects of the subject to within acceptable focus.)

You may have noticed that each control contains values that appear to double for each "Stop". This is based on the mathematical formulas for lens construction, photo sensitive elements, and a perfectly exposed image. The formulas resolve into a logarithmical equation and approximate each value for the respective user control. However in modern film and digital cameras it is not required to hit the exposure values exactly for the scene to be captured, there will always be elements within the scene that will violate the rules of mathematics. If used wisely our modern cameras can compensate for these photographic errors.

The important thing to remember is to begin using a set value as your standard settings; such as ISO=200. From that point on you can adjust shutter speed and aperture openings to capture the best exposure possible.

Another important thing to keep in mind is when you change one basic setting you will affect one or two others for a given exposure. Example: If you change the ISO=200 to ISO=400 the sensitivity of the camera will double and a corresponding reduction in light will have to be made to acquire the same good exposure. You may have to increase your Aperture one stop. or increase your shutter speed one stop.

The only way you will know for sure is to practice over and over using a standard subject model with standard lighting.