Back in 2001 when I was a sophomore, I took a 100 level photography course. I learned some basics that have stuck with me all these years. I figured I’ll summarize them here mostly for my own sake. Some friends of ours were visiting during the weekend and one of the topics of conversation was photography. That’s what prompted me to write this entry.
The most basic concept I suppose is “exposure.” Wikipedia defines exposure as “the total amount of light allowed to fall on the photographic medium.” A photograph must be correctly exposed, meaning the amount of light that falls on the film in older styles of camera or on the CCD (coupled charged device) on newer digital cameras must be just right. Correctly exposed pictures include the finer details.
Traditionally, there have been two ways to control the amount of light that enters the camera – aperture size and shutter speed.
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| Aperture Size Ref: Wikipedia |
As can be interpreted from the name itself, aperture size is the size of the opening of the lens. The values 1.4, 2, 2.8, 4, 5.6, 8… are listed on a camera to represent aperture size. The actual size can be calculated using the focal length of the lens (represented by ‘f’) divided by these values. Hence, 1.4 is the largest aperture size and allows the maximum amount of light to enter.
Shutter speed refers to how long the shutter or screen in front of the film or CCD opens up for. The longer it remains open, the more light falls on the light sensitive material. It may be safely concluded that the correct exposure will require faster shutter speeds for large aperture size and slower shutter speeds for smaller aperture size.
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| Shallow DOF to blur background |
Aperture size gives a photographer control over “depth of field.” Our friend Wikipedia defines DOF as “the distance between the nearest and the farthest objects in a scene that appear acceptably sharp in an image.” If you want the viewer’s focus on the subject and the background needs to be blurry because it competes for the viewer’s attention, then you want a shallow DOF. It can be achieved by setting a large aperture. On the contrary, most of the landscape pictures will need the smallest possible aperture to have an infinite DOF.
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| Slower shutter speed to capture motion |
Shutter speed is mostly important while taking pictures of moving objects among other things. Fast shutter speed freezes the motion while appropriately slow shutter speeds will capture the motion effect in a still photograph. Tripods can make life a whole lot easier while taking pictures that require slower shutter speeds.
Well, these are the basic things I remember (well not exactly, I had to look up a few things in Wikipedia ). I recently bought a Canon Rebel DSLR after having shelved my analog Pentax SLR for almost a decade now. Hopefully, I’ll get back in the habit of taking a few pictures.
