EXPLANATION OF TERMS. Sigma SD14

EXPLANATION OF TERMS

AE

Auto Exposure; by using a built-in exposure meter, camera determines the correct exposure value, which is combinations of shutter speed and/or aperture value.

AE Lock

The camera will fix and memorize the exposure value with AE lock. For example, if a photographic subject is placed in the center and exposure value of the composition is fixed, the brightness of the background will not influence the exposure, even if the composition changes and the subject is moved from the center of a screen. (AE lock button must be used).

AF

Auto Focus; by using a built-in sensor, camera adjusts the focusing automatically.

AF Lock

In AF shooting mode, you can lock the focus on the main subject. For instance, compose the desired subject in the center of the viewfinder. With the focus fixed at the same setting, you can re-compose the picture with the subject off-center and take shots. (Please press the shutter button “Half-way” to use this feature with Sigma SD14).

Aperture

The lens opening of the iris diaphragm inside the lens. The amount of light, which strikes the image sensor, is adjusted by the iris diaphragm. The f-number (Focal

Length/Diameter of the Aperture Opening) describes the size of this opening, the size of the hole can be made larger or smaller. Large aperture (low f-number) gives bright results and, small aperture (high f-number) gives darker results.

Auto Power-Off

For saving the battery power, the SD14 camera can automatically turn itself off, if you do not operate it.

CMOS

Complementary Metal Oxide Semiconductor (CMOS) can perform signal amplication on a per-pixel basis. Significant current flows only during the switching operation. Therefore a CMOS image sensor can scan data rapidly, sustain high-speed operation and consume less energy. Recent technological and production improvements in digital imaging systems are making CMOS more and more competitive in terms of image quality and cost.

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Color Temperature

The numerical expression of the tone of the light, produced by a light source. The standard unit for color temperature is degrees Kelvin (K). The sunny daylight used as a standard near 5600 K. Low color temperature implies warmer more yellow/red light while high color temperature implies a colder more blue light. The typical color temperature of Tungsten light is 3200 K grade, a personal computer is 9300 K.

Exposure.

The amount of light reaching the image sensor’s surface. The exposure is controlled by the combination of aperture and shutter speed.

EV

Exposure Value (EV) is a numerical value that expresses the amount of light for a given exposure, and depends on brightness of the photographic subject and sensitivity of the film. If a photographic subject is bright, then this numerical value will be large, and if the subject is dark then this numerical value will be small. If two-times of light reaches the film surface then the difference in exposure value will be +1, and if the amount of light is reduced by half, the exposure value changes by -1.

Histogram

The histogram function is a graphic representation of how bright and dark pixels are distributed in an image. The histogram function enables a precise check on the exposure of the photo.

ISO Sensitivity

ISO（International Organization for Standardization）; refers to the number assigned to each silver halide film, which indicates film speed or the film's relative sensitivity to light, the higher the number, the greater photosensitivity and vice versa. Digital cameras also use standard ISO sensitivity ratings like silver halide films.

JPEG

Joint Photographic Experts Group has established a standard method for compressing and decompressing the digitized images. If the rate of compression is high the file size will be small but picture quality will be decreased.

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Microdrive

Developed by IBM, the Microdrives are extremely small-sized hard disks that can fit in a CompactCard memory slot. The Microdrive is built into a Type II

CompactFlash form factor.

NTSC

National Television Standards Committee (NTSC) video format is primarily used in the United States, Japan, Canada etc. The NTSC is a standard for television and videos, which defines a composite video signal with a refresh rate of 60 half-frames (interlaced) per second. Each frame contains 525 lines and can contain 16 million different colors.

PAL

Phase Alternating Line (PAL), video format primarily used in Europe, excluding

France, as well as Australia and parts of the Far East. PAL delivers 625 lines at

50 half-frames per second.

RAW

The RAW image format is the data as it comes directly from the image sensor of the camera. No in-camera processing is performed before transferring the image to computer.

Shutter Speed

The camera’s shutter opens for a length of time to control the amount of light that reaches the imaging element. The length of time that shutter blinds are open allowing light to strike the image sensor is called as shutter speed.

White Balance

The human eye and brain adapt to changes in lighting conditions, not only to intensity, but also to the color characteristic of the light source, so that colors of the objects look normal or accurate. For example, a white object will appear white whether it is viewed under sunlight, tungsten or fluorescent illumination. However, color film or digital camera must be adjusted, so that colors will be represented accurately, under different types of illumination. This adjustment is called white balance. The function to adjust a white balance automatically is called automatic white balance.

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