Camera Settings: What Do They Mean? Sept 17, 2009 17:41:08 GMT -5
Post by Mary on Sept 17, 2009 17:41:08 GMT -5
Definition: The aperture is the size of the adjustable opening inside the lens, which determines how much light passes through the lens to strike the image sensor. A digital camera's aperture is measured in f-stops, and higher f-stops signify a smaller amount of light. The aperture changes, depending on the camera's settings for a particular shot.
CCD (Charge Coupled Device)
Definition: A CCD, short for charge coupled device, is the silicon chip inside the digital camera that records the image.
The CCD contains millions of capacitors. As light enters the camera through the lens, it strikes the CCD's photoactive layer, which causes each capacitor to accumulate an electric charge based on the amount of light that strikes it. The digital camera then converts the charge to pixels that make up the photo.
Definition: Exposure metering is the digital camera's built-in system that measures the amount of external lighting in a scene and then determines the best automatic settings for the photograph. Three modes of exposure metering are common:
· Center weighted metering is a mode where the digital camera measures the external light in an area around the center of the frame. It works best for portrait photos.
· Matrix metering is a mode where the digital camera divides the scene into segments, measures the lighting level in each segment, and then determines the automatic settings based on which settings would be correct for the largest number of segments. This mode, sometimes called multi-segment metering or multi-pattern metering usually has the best exposure results.
· Spot metering is a mode where the digital camera only measures the lighting in a tiny spot in the center of the frame.
Definition: Flash is an artificial source of extremely intense light that can be added to photos shot with a digital camera. The flash fires just before the photo is snapped, giving the lens and image sensor plenty of light with which to record the digital image. Flash can refer both to the flash of light that occurs when the flash fires, as well as the actual flash unit that creates the light.
Definition: Focal length is the distance from the center of the lens in the digital camera to the focal point. Focal length is measured in millimeters, and it's usually expressed as a 35mm film equivalent.
A lens that matches human vision with no telephoto or wide-angle capabilities applied to the lens is about 50mm. Wide-angle capabilities, usually considered anything less than 35mm, provide a larger field of view (FOV). Telephoto, or zoom, capabilities, usually considered anything greater than 70mm, provides a smaller FOV.
IS (Image Stabilization)
Image stabilization (IS) is a family of techniques used to increase the stability of an image. It is used in image-stabilized binoculars, still and video cameras, and astronomical telescopes. With still cameras, camera shake is particularly problematic at slow shutter speeds or with long focal length (telephoto) lenses. With video cameras, camera shake causes visible frame-to-frame jitter in the recorded video. In astronomy, the problem of lens-shake is added to by variations in the atmosphere over time, which cause the apparent positions of objects to change.
Definition: ISO is a number used to express the light sensitivity of the digital camera. ISO has its origins in film photography, where the ISO setting measured the sensitivity of a particular roll of film to light.
With a digital camera, you usually can shoot at a variety of ISO settings. Higher ISO settings allow you to shoot digital photos in low-light conditions, but such photos are more susceptible to noise and grainy images than photos shot at low ISO settings.
Definition: JPEG, short for Joint Photographic Expert Group, is the most commonly used type of formatting for image files created with a digital camera. JPEG, pronounced jay-peg, is a form of compression that reduces the file size significantly, allowing you to fit more photos on a memory card. JPEG is especially useful for beginner photographers.
With most beginner-level digital cameras, the photographer can choose between a few different levels of JPEG compression. As you apply more compression to digital image files, image quality suffers. Sometimes, highly compressed JPEG photos can end up with artifacts, which are image distortions that the compression causes in the file.
To make high-quality, large prints with JPEG images, select as little JPEG compression as possible.
Definition: Resolution is the measurement of the total number of pixels that a digital camera's image sensor can record in one photograph. Digital camera resolution is expressed in megapixels, which are millions of pixels.
Theoretically, digital cameras with higher resolutions can create sharper and larger print photographs. However, high-resolution cameras don't automatically yield high-quality photos, because many factors contribute to photo quality, such as lens quality, shutter speed, and external lighting.