Glossary of DSLR Camera Terminology

Glossary DSLR Camera

3x, 5x, 10x – The focal length ratio of a zoom lens.

Add-On Lens – Some lenses have threads on the front edge that allow you to mount a wide angle or telephoto lens on top of the standard lens.

AE – Auto Exposure, automatically sets the exposure according to the existing light conditions.

There are three types:

  • Programmed – the camera picks the best shutter speed and aperture automatically.
  • Aperture Priority – The user chooses an aperture value and the shutter speed is automatically determined by lighting conditions.
  • Shutter Priority – The user chooses a shutter speed and the aperture is automatically determined by lighting conditions.

AE Lock – Allows you to use the current exposure settings and point the camera at a different subject before taking the picture.  This is usually accomplished by half pressing the shutter button and keeping it at that position until you are ready to take the picture.

AF – Auto Focus.

Anti-Shake – The mechanical shifting of the imager to compensate for camera movement.  This helps eliminate blurring at slower shutter speeds.

Aperture – The size of the opening in the camera.  The aperture is automatic in most digital cameras, but some allow manual adjustment to give you more control.

Aspect Ratio – The ratio of horizontal to vertical dimensions of an image.  The most common aspect ratio in digital cameras is 4:3 so that images look better on a computer screen.

Autofocus – The camera lens focuses automatically, usually when the shutter release is pressed half way.

Buffer – A temporary storage area usually held in RAM.

Burst Mode – The ability to rapidly capture images as long as the shutter button is held down.  Also known as Continuous Frame Capture.

Byte – A set of eight bits of memory in a computer.

Calibration – Adjusting the color of one device relative to another.

CCD – Charged Coupled Device, A light sensitive chip used for image gathering.  Similar to CMOS.

CMOS – Complementary Metal Oxide Semiconductor.  An imaging system used by digital cameras.  It is not as popular as CCD, however, in the future we will have even better digital cameras based on CMOS sensors as they require less power than the CCD device.

Compact Flash (CF) – Older digital camera flash memory storage.  This process is now performed by Secure Digital (SD) cards.

Compression – A digital image is a extremely large.  A low-resolution 640 x 480 image has 307,200 pixels.  To make image files smaller, most digital cameras use compression.

Continuous AutoFocus – Autofocus system is enabled at all times and focusing is automatically accomplished by the camera system.

Contrast – A measure of the rate of change of brightness in an image.

Crop Sensor – Means you are printing only part of the image that is in the slide or negative.  It may also refer to framing the scene in the viewfinder.

Dedicated Flash – Describes an electronic flash created for use with one specific camera.

Digital Zoom – A digital magnification of the center 50% of an image. Digital zoom will create inferior images.

Exposure – The amount of light that reaches the image sensor and is controlled by the lens system and shutter speed.

Fixed Focal Length – A term that describes a non-zoom lens, fixed at a given focal length.

Focal Length –  The difference between the lens and the surface of the sensor.  It determines the magnification or zoom.

ISO – The speed or specific light sensitivity of a camera. The higher the number, the more sensitive it is to light.  This is determined by the standards of the International Standards Organization.

LCD – Liquid Crystal Display.  Used in the viewfinder window.

LED – Light Emitting Diode.  The many multicolored lights used on cameras.

MB – Megabyte, memory term meaning 1024 kilobytes.

Megapixel – CCD resolution of one million pixels.  Digital cameras are rated by megapixels.

NEF – Raw image data file format used by some DSLR’s.

Noise –pixels in your digital image that were misinterpreted.  Produced as groups of Red, green or blue pixels.  Can occur when you shoot a long exposure over ½ second or when using the higher ISO values from 400 or above.

Optical Viewfinder – A viewing screen on a camera that allows the photographer to see what the image will be.  Also known as a finder and projected frame.

Pixel – The individual imaging element of a CCD.  Today, this number varies between 1 million (1 Megapixel – MP) to 14 million (14 Megapixels – MP).  There are a million pixels in A 1MP camera and 3 million pixels in a 3MP camera.  Most digital cameras have between 2MP and 5MP.   A 4MP camera is recommended for images 8” x 10” or higher.

RAM – Random Access Memory.  The Central Processing Unit stores software, programs, and data that are currently being used.  When the computer is turned off, the contents of RAM are lost.

RAW – RAW files store the unprocessed image data.  Lossless compression is applied to reduce file size slightly without compromising any quality.  RAW files must be processed with special software before they can be viewed or printed.  The advantage is that you have the ability to alter the white balance, exposure value, color values, contrast, brightness and sharpness as you see fit before you convert this data into the standard JPEG or TIFF format.

Red-Eye – An effect caused by an electronic flash reflecting off of the human eye and making it look red.  There are software options to remove red eye.

Resolution – The quality of any digital image.

RF – Range Finder – A type of camera viewfinder that uses one lens to frame your subject and another lens to capture the image.

RGB – Red, Green, Blue – The primary colors from which all others or derived.

Saturation – The degree to which a color is undiluted by white light.  If a color has no saturation, it is a shade of gray.

Sensitivity – Sensitivity settings on digital cameras are the same as ISO ratings on film.  Better cameras have larger sensors and better sensitivity.

Sensor Size – Usually the sensor size if very small.  About the size of a fingernail.  You will have better image quality with a larger sensor.

Shutter Speed – The amount of time that light can pass through the aperture.  The light sensor in a digital camera can be reset electronically.  Digital cameras have a digital shutter.

Viewfinder – The eye level device you look through to compose the Image.

White Balance – Refers to adjusting the relative brightness of the red, green and blue components so that the brightest object in the image appears white.  You can pick your white balance to suite your light source so that white looks white, not yellow or blue.

Zoom (Digital Zoom and Optical Zoom) – Most cameras have optical zoom and digital zoom.  With Optical zoom, the lens changes focal length and magnification as it is zoomed.  Image quality stays high throughout the zoom range.  Digital zoom simply crops the image to a smaller size, and then enlarges the cropped portion to fill the frame again.  Digital zoom results in a significant loss of quality.

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