Over the next few posts I want to share some basic, but fundamental, information about what goes into creating a photograph.
All of photography can be discussed in terms of light. The ability to see subtle changes in the light on a subject is a key to high quality work and is part of what makes a photograph rather than a snap shot. The challenge is to control the light.
Light can do more than make an image; it can emphasize, subdue or alter moods. It can help you say many things about your subject.
The first property of light to deal with is it’s intensity or brightness. The key is making sure that there is enough to make an image. The light that enters our camera lens is either direct light from a light source such as the sun or light bulb or it is reflected light that has bounced off people or things. To capture an image, the film or sensor must be exposed to light. The correct exposure (amount of light) for any scene is the exposure that gives the image you want. There may be a variety of possible exposures that will work. Other scenes may have a greater range of light levels than the camera and film or sensor can cope with. For these, a certain level of exposure will be applicable. Sometimes a technically incorrect exposure will give the image the desired artistic effect.
Taking a correctly exposed image means that the right amount of light has been exposed to the image sensor or film. There are a number of factors that affect a correctly exposed image, three of which can be adjusted on the camera (or film):
- opening or closing the aperture
- deciding how long to leave the shutter open;
- adjusting the sensitivity (ISO);
All three factors will be looked at in separate blog posts following this one.
There are two problems encountered on images taken, with regard to exposure:
Underexposure occurs when the image taken comes out dark (image on the left below). i.e. there’s too little light.
Overexposure occurs when the images taken comes out too bright i.e. there’s too much light. If the aperture cannot be closed enough and/or a faster shutter speed used, the result will be an overexposed image.
If you have enjoyed reading this please read some more tips on setting your Aperture.
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