I. Digital SLRs are dirt cheap these days. We see more and more people purchasing Digital SLR on a daily basis but quite often these newbies are also pretty much disappointed at how they were promised beautiful pictures yet fail to achieve.
II. My topic is the canon DSLR and how to take a correctly exposed photo
III. I picked this topic because digital photography is my major
IV. When the shutter button is pressed, the camera takes the shot based on the shutter speed, aperture and ISO set on the camera – these 3 factor holds greatest influence on the exposure of your shots. The aperture blades close in, the shutter lifts and the light lands on the sensor, the camera captures it.
I. Shutter Speed
A. So what is shutter speed? Shutter speed is the setting on your camera that decides how long the shutter should open. The longer the shutter opens, the more the amount of light is captured on the sensor. This is a mirror though, behind it is the shutter, which is right in front of the sensor.
B. Think of it as your eye lids. The shutter is basically a closed eye lid, once the shutter button is clicked, the eye lid opens and closes. By setting the shutter speed, you’re telling the camera to duration to keep the eye lid open.
C. For our human eye, the longer the eye lid is open also means more light has entered the eye. Stare at some bright lightbulb for half a second and your eyes barely hurt. Stare at the bright lightbulb for 5 seconds and you’re stuck with the ghost of the lightbulb. The same concept applies to shutter. Assuming all factors (like aperture and ISO) remain the same, the longer the shutter is opened, the more exposure you get – which is why another common term for Shutter Speed is EXPOSURE TIME.
II. Aperture
A. Aperture refers to the diaphragm opening inside a lens. How wide the aperture is open is indicated by the F-number. The lower the number, the wider it is. The wider it is, more light goes through it.
B. Think of it at your eye