Tuesday, December 05, 2006
Relationship of Aperture, ISO, and Shutter speed
So, you may ask, what are these labels for that you see on your digicam knob/ wheel? Just got these from www.DPreview.com, read on! ^__^
exposure basics
ISO (or Sensitivity)
relationship of aperture and shutterspeed
Shutter Speed
Aperture
Refers to the size of the opening in the lens that determines the amount of light falling onto the film or sensor. The size of the opening is controlled by an adjustable diaphragm of overlapping blades similar to the pupils of our eyes. Aperture affects exposure and depth of field.
exposure basicsConventional film comes in different sensitivities (ASAs) for different purposes. The lower the sensitivity, the finer the grain, but more light is needed. This is excellent for outdoor photography, but for low-light conditions or action photography (where fast shutterspeeds are needed), more sensitive or "fast" film is used which is more "grainy".
relationship of aperture and shutterspeedShutter Speed
The shutterspeed determines how long the film or sensor is exposed to light. Normally this is achieved by a mechanical shutter between the lens and the film or sensor which opens and closes for a time period determined by the shutterspeed. For instance, a shutter speed of 1/125s will expose the sensor for 1/125th of a second. Electronic shutters act in a similar way by switching on the light sensitive photodiodes of the sensor for as long as is required by the shutterspeed. Some digital cameras feature both electronic and mechanical shutters.
# posted by Brando @ 2:53:00 AM 
