Exposure  Exposure is the most important concept of Photography. A photograph's exposure determines how light or dark an image will appear when it's been captured by your camera and it determined by just three camera settings: aperture, ISO and shutter speed (the "exposure triangle"). If the shot is exposed too long the photograph will be washed out. If the shot is exposed too short the photograph will appear too dark. Almost all cameras today have light meters which measure the light in the given shot and set an ideal exposure automatically. Q: How does the Exposure triangle work and how are aperture and shutter speed related to each other? Ans: The two primary controls your camera uses for exposure are shutter speed (the amount of time the sensor is exposed to light) and aperture (the size of the lens opening that lets light into the camera). Shutter speeds are measured in seconds and more commonly fractions of a second. (1/2000 of a second is very fast and 8′ seconds is extremely slow). Apertures are measured in something called f/stops (a very wide aperture is f/2.8 and a very small aperture is f/19).

You can use different combination of aperture and shutter speed to achieve exactly the same exposure-if the aperture is small, the shutter must stay open for longer to allow the required amount of light to expose the film, whereas, if the aperture is wide, the shutter doesn't need to be open for as long. The combination you choose will depend on what your subject is. For sport and action, fast shutter speed is required to freeze movement, so 1/1000 sec at 2.8 would be ideal, whereas for landscape a small aperture is more important as you need maximum depth of field. Q: How does my camera measure the light and calculate the exposure? Ans: All cameras with an integral meter use a system known as TTL (Through the lens) metering to measure the light passing through the lens. The light which is measured is actually the light which is reflected back from your subject and how light and dark your subject is, would influence the reading obtained

Q: When I shoot against a light or dark background, the pictures always come out either too light or too dark. Why is this? No matter how modern the camera would be, it isn't totally foolproof and can still lead to a wrong exposure. The reason behind this is that your camera settings measures light bouncing back off your subject. Also some colors and surfaces reflect more light than others. In exactly the same lighting conditions, white subject will reflect more light and black subject will reflect less light. Also your camera is calibrated to record everything as a mid-tone known as 18% grey. So your camera will always record it as mid tone.

❏ Subject against a light background

This is one of the most common lighting situations. In a situation like, when you are trying to photograph a person against a white background, white wall or white sky. Due to the brightness of the background, your camera meter is fooled and so it underexposes and your subject comes out dark

❏ Subject against a dark background

In such a situation, the photograph usually comes out to be really bright as your camera tries to expose for dark background and its lightens the entire image. Q: Do handheld meters offer any advantage over the light meter? Ans: Yes, a light meter is better as it's a incident light meter and it reads the light which is actually falling on your subject, rather than the light which is reflected back.