Photography - 4

Photographs are created by exposing light on a photo sensitive material, earlier it was films and now it is a sensor in a digital camera.

A photograph is dependent on three factors to control the quantity of light required.
1. Shutter speed
2. Aperture
3. Sensitivity of film/sensor
In the above diagram, I’m using a quantity of water as an analogy for the quantity of light.
First let’s look at Shutter Speed – it is a measure of how fast the camera shutter opens and closes. This determines the amount of light that is entered. We need more light in dark and less light when the surroundings are bright.
Shutter speed is measured in seconds. ( 1/30s is larger than 1/1000, in cameras it is shown as 30, 1000 etc.)
Next we look at the aperture; it is nothing but the opening through which the light travels. It is normally denoted by f-number. (f/2.8, f/4,f/8,f/16 etc.)
Smaller the f-number larger the aperture, more quantity of light is allowed to pass through.
The last factors is Sensitivity, it is measured in ISO number, lower the ISO number more sensitive the film or the sensor. The advantage of digital camera is, you can set the sensitivity. Earlier in film cameras the sensitivity was fixed. (like Kodak 200,400 etc) . Typically the ISO value ranges from 100 to 1600.
In digital camera you can play around with these three parameters to get a perfect photograph.
Apart from these parameters the most important element that impacts your photograph is the type lens used. (below 21 mm as Macro, 35mm medium, 50mm normal, 85-135 Telephoto/zoom, above 300mm Super Telephoto)
Go ahead and experiment !