Exposure is the total amount of light allowed to fall on either the image sensor (if using a digital camera) or photographic film (if using an older film camera) during the process of taking picture.

A camera uses two things to control the amount of incoming light (exposure):

Shutter Speed - Determines how long the shutter stays open.

The 'shutter' (the small shutter at the front of your camera) is in the closed position (to stop light getting in) until you press the shutter button on your camera. It will then open and close for the length of time either you (manually) or the camera (automatic) have set it for.

Aperture - Controls how much light is passed through the lens.

When light passes through a camera's lens, it must pass through an opening called the "Aperture". In layman's terms it's like the pupil in a human eye. It lets more light in when opened, less when closed (so depends on how much or how little it is 'opened'). See Aperture Explained for more details.

Exposure is about different combinations of shutter and aperture settings.

Here's an example to show correct exposure, along with over and under exposure:


Over exposed means you let it too much light, hence the image is too bright/blown, or the lighter areas are effected most.

Under exposed means you didn't let in enough light, so the image will be too dark, with darker areas of the image being affected the most.

Correct exposure means just that.

So if your photos are coming out dark, they are under exposed, and you will either need to use a longer (slower) shutter speed, or increase the ISO*. Alternatively you could buy a more powerful flash.

On the other hand, if they are too bright they are over-exposed, and you need a shorter (faster) shutter speed.

These are just the basics, but should have you well on your way

*To learn more about ISO, see: ISO Explained

Thanks for that. That was nice and easy to understand

Thanks Carole Im very much a simple person who needs and gives simple explanations

Nice one K! We need to start a sticky thread that lists such guides methinks

Nice one, made sense, unlike the manuals that come with most cameras.

I agree - at this rate I'll not need to read the book

But what about ISO?
Its the fourth parameter. Just as important as the other three.

Tom

ISO is covered on another thread but yes your right.

Even I understood that KK, thanks

Brill , thanks for that... 100 pages of the manual condensed into one easy lesson