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Photography Terms


Aperture is the unit of measurement that defines the size of the opening in the lens that can be adjusted to control the amount of light reaching the film or digital sensor.

Aperture Priority

Aperture Priority is a setting that allows the user to select a static aperture and the camera automatically selects the shutter speed to achieve the proper exposure.


In photography, bokeh, is the aesthetic quality of the blur produced in the out-of-focus parts of an image produced by a lens.


The camera normally determines the optimal exposure. There are times where it is advantageous to capture images that are slightly under and over exposed. This is called bracketing.

Chromatic Aberration

Also known as “color fringing,” this distortion appears when the camera lens fails to focus on all the colors where two points of high contrast meet.

Depth of Field

Depth of field refers to the part of the image, from foreground to background, that is in focus.

Exposure Compensation

Exposure compensation is a technique for adjusting the exposure indicated by a photographic exposure meter.

Exposure Value

The exposure value (EV) is a number that represents a combination of a camera’s shutter speed and aperture, such that all combinations that yield the same exposure have the same EV value.


A diaphragm inside the camera lens, known as the aperture, can be opened or nearly closed, to regulate the amount of light that falls on the image sensor.

File Types

There are five primary file types in digital photography. The most common file type is JPEG.

Film Speed

Film speed is the measure of a photographic film’s sensitivity to light.

Focal Length

Focal length is an optical measurement that determines how much of what you see in front of you is captured by your camera’s lens.

Focus Stacking

Focus stacking is a digital image processing technique which combines multiple images taken at different focus distances to give a resulting image with a greater DOF.


High-dynamic-range imaging (HDRI or HDR) is a set of techniques used in imaging and photography to reproduce a greater dynamic range of luminosity than is possible with standard digital imaging or photographic techniques.


In photography, a histogram is a type of chart that acts as a graphical representation of the tonal distribution in a digital image.


For ISO see Film Speed.

Mirror Lock-Up

Mirror lock-up (MLU) is a feature employed in many Single Lens Reflex (SLR) and DSLR cameras. It allows the operator to reduce vibration-induced motion blur during exposure.

Shutter Speed

Shutter speed is one of several methods used to control the amount of light recorded by the camera’s digital sensor or film.

The 500 Rule

During long night sky exposures the starts appear to be moving across the sky due to the earth’s rotation. This causes what are most commonly referred to as “star trails”. Sometimes this is a desired effect but most often we try to eliminate them where possible. Especially when photographing the Milky Way. For this reason, The 500 Rule was created.