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FAQ: Common Photographic Terms & Abbreviations
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Feb 20, 2012 03:14:38   #
AF = A-F = Auto-Focus.

Aperture = a diaphragm "window" built-in to every lens. Camera lens apertures are usually adjustable. Telescopes, binoculars and camera "reflex" mirror lenses have fixed apertures.

APS-C = most common size of sensor in DSLR camera. Canon = 22.2-mm x 15-mm; all other manufacturers are 24-mm x 16-mm.

Av = Aperture value, which is Canon speak for Aperture (f/stop).

Base ISO = The lowest ISO a camera sensor will record without resorting to software interpolation. It is also the lowest number listed in ISO range of each camera. AKA Native ISO.

Bit Depth = The number of bits used to hold a pixel. Also called "color depth" and "pixel depth," the bit depth determines the maximum number of colors that can be displayed at one time. True Color (16M colors) is required for photo-realistic images and video. Most display adapters today support 65K and 16M colors at their highest resolution without noticeable loss of performance in rendering the images.
Bit depth = Number of colors
4-bits = 16 (Standard VGA)
8-bits = 256 (Super VGA, indexed color)
16-bits = 65,536 (High Color)
24-bits = 16,777,216 (True Color)
32-bits = 16,777,216 + alpha channel

Bokeh = background highlight spot blur (I hate this term!). Appropriate term is "Circles of confusion".

bpc - bits per channel (Photoshop)

Bracketing = A set (usually 3 or 5) of exposures at different EV (Exposure Value) settings, with the variable usually being shutter speed (rarely aperture), most often separated by 1-stop or 2-stops. Used in making a single HDR imaging, or to assure proper exposure in a difficult photography situation.

B&W = Black & White (film)

Camera lens focal lengths are usually specified in millimeters (mm). When a photographic lens is set to "infinity", the distance between its rear nodal (focal) point and the sensor is the lens' focal length.

CC = Constructive Criticism

CCD = Charged-Couple Device = = sensor inside SOME camera.

CF = Continuous Focus

CMOS = Complementary Metal–Oxide–Semiconductor = = sensor inside MANY cameras.


CoC = Circle of Confusion = In photography, used to determine the depth of field, the part of an image that is acceptably sharp. A standard value of CoC is often associated with each image format, but the most appropriate value depends on visual acuity, viewing conditions, and the amount of enlargement. Properly, this is the maximum permissible circle of confusion, the circle of confusion diameter limit, or the circle of confusion criterion, but is often informally called simply the circle of confusion.

CPF = Circular Polarizing Filter (sometimes mis-labeled as CPL). NOT the same as Linear Polarizing Filter.

CS1, CS2, ... CS5, CS5.5 = PhotoShop versions (CS6 is coming soon)

DOF = Depth of Field (area acceptable focus within photo).

DPI - Dots Per Inch (printer reference)

DSLR = Digital Single Lens Reflex camera

EXIF = Exchangeable Image File, a format standard for storing information in digital image files using JPEG compression.

EXIF Info = Information about camera, lens, and settings used to capture an image, which is imbedded by the camera, within all JPEG original images. Exif info is often stripped-away when only "thumbnails" (no enlargement) images are posted.

Extension tube = empty mechanical tube, placed between camera and lens, to increase size of image striking sensor. An Auto-Extension tube has electronic connectors so camera and lens can continue to communicate auto-focus & auto-aperture.

f-stop = measurement of aperture opening, expressed as a (f)raction, such as f/16. The bigger the number = the smaller the aperture.

Focus Breathing = the change of focal length (and hence angle of view and magnification) when the focus distance of a lens is changed.

Focus Stacking = A final single image composed from at least two original digital captures, each displaying a different part of subject in focus. Most useful in macro-photography, where DoF is always quite shallow. By combining several shallow DoF images of a stationary subject, a single image with extended DoF can be rendered. A Focus Stacking program must be used to compile images.

Four/Thirds System = 4/3 = sensor size of 17.3-mm x 13-mm.

Full Frame = sensor size of some DSLRs 36-mm x 24-mm, matching image size of 35-mm cameras.

GAS = Gear Acquisition Syndrome, a near-fatal malady that can only be remedied by proper application of VISA or M/C. Brand specific syndromes are the worst, such as NGAS (Nikon), CGAS (Canon), PGAS (Pentax), SGAS (Sony), OGAS (Olympus), etc.

HDR = High Dynamic Range = A set of techniques that allows a greater dynamic range between the lightest and darkest areas of an image than current standard digital imaging techniques or photographic methods. This wide dynamic range allows HDR images to more accurately represent the range of intensity levels found in real scenes, ranging from direct sunlight to faint starlight, and is often captured by merging (with an HDR computer program)of multiple, differently exposed standard-dynamic-range digital images of same subject.

HHCC = Hard Hat Constructive Criticism (meaning, mostly criticism, and less constructive)

Hyperfocal Distance = the point of focus where everything from half that distance to infinity falls within the depth of field = the distance setting at any aperture that produces the greatest depth of field. More here:

IMO = In my opinion = IMHO = In my honest opinion (meaning anything I said previously was not honest) or "humble opinion" (labeling self as humble?)

Intervalometer = An electronic device used to trigger a digital camera, to make a series of exposures for time-lapse images, such as star trails. It may also be used to take picture(s) after a set time delay.

IQ = Image Quality

IS (Canon & Olympus) = Image Stabilization = VC (Tamron) = Vibration Control = OS (Sigma) = Optical Stabilization = VR (Nikon) = Vibration Reduction.

ISO (International Standards Organization) = old ASA (American Standards Association) = measurement of CCD or CMOS or film sensitivity to light. The higher the ISO = increased sensitivity to light (good) = increased noise (bad).

JMO = Just my opinion

JPG = JPEG = a lossy compression technique for color images, established by the Joint Photographic Experts Group.

LR, LR2, LR3 - LightRoom versions

MF = Manual focus

MFD = Minimum Focusing Distance (between sensor plane to subject).

Native ISO = The lowest ISO a camera sensor will record without resorting to software interpolation. It is also the lowest number listed in ISO range of each camera. AKA Base ISO. When a camera is re-set to "manufacturer" or default settings, the ISO will return to Native ISO.

Noise = electronic aberrations (mis-fired pixels) occurring on CCD or CMOS sensor. Comparable to "grain" in film images.

OCF = Off Camera Flash

OOF = Out of focus

PHOBAR = Acronym for "PHOtoshopped Beyond All Recognition."

Pixel = a single microscopic sensor, to capture light and color, within CCD or CMOS. A 12M sensor has 12-million pixels.

PP = Post Processing

PPI - Pixels Per Inch (CMOS sensor reference)

PSE1, PSE2,. . . = PhotoShop Elements - latest version 10

P&S = Point & Shoot camera

RAW = raw image file contains minimally processed data from the image sensor of either a digital camera, image scanner, or motion picture film scanner. Raw files are so named because they are not yet processed.

Reversing Ring = a ring that has camera body attachment mount on one side, and is threaded on the other, to mount on your lens where you normally mount your filter. A lens mounted in reverse position dramatically increases magnification, but loses all automated function. Manual focus and manual adjustment of both aperture & shutter speed are required.

Sensor = the image collecting part of a digital camera. Common sizes are 'Full Frame' (36-mm x 24-mm). APS-C (24-mm x 16-mm), APS-C Canon (22-mm x 15-mm), Four/Thirds (17.3-mm x 13-mm).

SF = Selective Focus

Shutter Duration = length of time shutter is open.

Shutter speed = inaccurate term for shutter duration (length of time shutter is open).

Slave = off camera flash

SLR = (film) Single Lens Reflex camera

SOOC = SOTC = Straight out of (the) camera

TIFF = Tagged Image File Format, a widely supported file formats for storing bit-mapped images on personal computers.

Tv = Time value, which is Canon speak for shutter duration.

uber-HDR = Overly tweaked HDR image.

WB = White Balance

WD = Working Distance (between lens front element to subject).

Additional definitions on Wikipedia:
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