In digital cameras and DSLRs, you have the option of aperture mode, which will give more importance to the focus length.
Aperture is basically the opening just like a window of your home or pupil of your eye which controls the amount of light that can pass and fall into the sensor.
Aperture mode is also referred to as Portrait mode in most cameras. So if you ask what you can do with this mode? Well, you can take stunning sharp images with blurred background if you set proper aperture values and shutter speed.
Take this image for example, the focus is on the tip of the pencil and rest of the background are blurred. You can have much better effect if you have a SLR or high end digital cameras. I took this picture with my Canon PowerShot A550, f/2.6, exposure time= 1.3sec, ISO 80, focal lenth 6mm.
|Picture taken by: Lisasolonynko|
Aperture is expressed as f/number ,where f = focal length and number = value that represents the size of the opening of the lens or simply 'f stops'. Lower the number value, narrower the focal length will be and hence sharpness of the image will be achieved at a smaller focal length. The usual aperture values are like f/1.8, f/2.6/ f/3.2, f/4, f/5.5, f/7.5, f/14, f/22 etc.,
To say simply, lower the number value means larger opening of the lens and hence more light to the sensor and hence sharper image with narrow focal length. For a landscape picture, you should use aperture values like f/14 or more for overall sharpness of the image and hence a wider focal length.
Some more examples of aperture mode in action.
|Picture taken by: Mau|