Learning with Your Digital SLR

What is Exposure?

27/10/09
Snowy Mountains, a difficult exposure where the snow's brightness may fool your camera's light meter.
Snowy Mountains, a difficult exposure where the snow's brightness may fool your camera's light meter.
When photographer's press the camera's shutter button to take a picture it is called "making an exposure". In an analogue (film) camera this was the period when the shutter snapped open and "exposed" the film to light. In a digital camera exposure happens when light lands on the megapixel sensor.

Early single lens reflex cameras (SLRs) were not the all singing machines which we use today. They were much simpler and often had only what is now called "manual mode".

If the photographer had a more expensive model it might have a built-in lightmeter which gave an indication of the correct shutter speed and aperture combination to choose. There was no "Green Auto Everything" mode which only requires a photographer to point his camera at a subject and press the button.

If green auto mode is being used the camera measures the light falling on the scene using a reflective light meter. It then sets three variables, the ISO or sensitivity, the shutter speed and the aperture.

The settings which the camera chooses will result in a pleasing picture at least 85% of the time.

Here I aim to teach you how to get better results and master the exposure meter and make the camera creative.