Sigma DP1 user manual Explanation of Terms, AE Lock

EXPLANATION OF TERMS

AE

Auto Exposure; by using a built-in exposure meter, the camera determines the correct exposure value, which is a combination of shutter speed and 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 pictures. (Please press the shutter button “Half-way” to use this feature with the Sigma DP1).

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. A large aperture (low f-number) gives bright results and a small aperture (high f-number) gives darker results.

Auto Power-Off

To save battery power, the DP1 camera will automatically turn itself off if it is not used for a period of time.

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.

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.

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