Photography Terms Cheat Sheet
Widely used photography and camera terms
By Inexorable in Articles and Tips on Jun 30, 2014
Being nearly two centuries old, photography is understandably replete with terms that span the archaic (ISO) to the contemporary (IS) and the arcane (EV) to the pedestrian (LV) . The problem is compounded by the well-known penchant of marketing whizkids to pitch new products using newly minted catchy abbreviations as props.
For a newcomer striving to get to speed in photography, it can be exasperating to be repeatedly confronted with terms such as PDAF and DOF while reading articles and following discussions.
At Pentax Forums, we feel your pain and wish to mitigate it with a compilation of widely used photography terms.
Read on for a glossary of photo terms which you can bookmark and/or print for reference! A follow-up article will dwell on terms associated with lenses and other photographic gear.
We have grouped our cheat sheet under two headings
- Photography Related Terms
- Camera Related Terms
Photography Related Terms
The opening of a lens, which determines the amount of light that reaches the sensor.
Birds in Flight Photography.
Bokeh is Japanese for blur, but in photography it refers to the subjective aesthetic quality of the blur. Specifically, how the highlights show up - with hexagonal or circular shapes- depending on the shape of the lens's aperture blades. Bokeh depends on the quality of a lens but can to some extent be controlled by varying the DOF with aperture (f-stop) setting.
Chromatic Aberration is color distortion that occurs because a lens refracts different wavelengths (colors) of light at slightly different angles. As a result, a lens is unable to focus all colors at the same convergence point. This results in color fringes along boundaries that separate dark and bright parts of the image.
DSLRs featuring sensors smaller than a FF sensor, don't "see" the full frame when fitted with a 35mm camera lens. The projected image is larger than the sensor and so gets cropped!
Crop factor is the ratio between the diagonal of a FF sensor and the diagonal of a smaller sensor. Crop factor for Pentax and most other DSLRs is 1.5x. Canon DSLRs have a 1.6x crop factor.
Crop factor narrows the FOV, as would a higher focal length (telephoto) lens; the Equivalent Focal Length (EFL) of a full frame lens fitted on a crop DSLR is computed by multiplying the focal length by the crop factor. For example, a 50mm lens on a Pentax APS-C camera would deliver the same field of view as a 75mm lens on full-frame. In other words, to get the same field of view on a cropped sensor, a shorter focal length is required. This is seen as advantageous for telephoto photography.
Depth of Field. The zone of reasonably sharp focus in terms of distance from the camera; DOF depends on focal length and aperture.
In the context of photography, Dynamic Range is the ratio between the largest and smallest measure of light. It is measured using base-2 logarithmic values, as the power or factor of 2. The measure is commonly expressed as f-stop. An increase in f-stop by 1 represents a doubling of the factor. An f-stop of 1 corresponds to a factor of 2, an f-stop of 2, to a factor of 4, of 3, to a factor of 8, and so on.
The human eye is estimated to have a dynamic range equivalent to 20 f-stops; digital SLRs have a dynamic range of 8-11 f-stops (newer cameras do increasingly better in this area), and an LCD monitor, 7-9 f-stops.
Full Frame. A full frame (36x24mm) image sensor roughly corresponds to the single exposure frame size of a 35-mm film. High end professional DSLRs use FF sensors. Most digital cameras use smaller (APS-C) sized sensors with crop factors varying from 1.5 to 1.6.
The distance in millimeters between the optical center of a lens and its focal point. The magnifying power of a lens depends on its focal length. Higher the focal length, greater the magnification.
As with Zoom Racking, you can sometimes achieve interesting effects by changing the focus during a long exposure.
Field of View. The extent of the scene that can be observed using the human eye or a camera lens.
Also called F number, is the measure of the aperture of a lens. A low F-stop, such as f/1.8 indicates a wide aperture (more light), while a high f-stop, such as f/16, indicates a narrow aperture (less light). F-stop is expressed as the ratio of the lens's focal length to aperture.
High Dynamic Range (HDR) photography is a technique to express the high tonal range of a scene as perceived by the human on an LCD display with limited tonal range. The technique involves capturing multiple photographs using different exposures to record the entire tonal range of a scene, and then mapping the tones to a single photograph, compressing the high dynamic range of the scene to the limited dynamic range of the LCD monitor.
High Key Photography
High key images have large areas of bright midtones, and smaller dark areas which are correctly exposed. For artistic effect, high key photos often contain blown highlights.
A distance beyond which all objects in an image will be acceptably sharp.
Depth of field is split 1/3 in front of the focus point, and 2/3 behind.
Landscape photographers take advantage of this to maximize the extent of sharp focus by focusing 1/3 of the way up the scene using maximum DOF. This is generally referred to as the Hyperfocal distance.
A graphical display of the tonal range of a given image. Based on the distribution, the histogram can show whether or not a photo is overexposed (skewed left), under-exposed (skewed right), or evenly-lit (evenly distributed).
ISO or Sensitivity
International Standards Organization. A measure of the sensitivity to light of the sensor or film. Higher the ISO, greater is the sensitivity.
Low Key Photography
Low key photos have large areas of dark midtones, and smaller highlighted area which are correctly exposed. Low key photographs look somber and can sometimes be more effectively rendered using black and white.
The term refers to the ability of a camera lens to greatly magnify the subject. Generally, lenses capable of rendering a subject on the sensor or film at near life size are referred to as Macro lenses.
Automatic calculation of exposure by a camera based on the light sensed. Metering can be spot, central or full scene.
Purple Fringing. In photography, CA shows up as PF.
PF is maximum when aperture is wide open and can be reduced by reducing aperture (increasing f-stop).
A relative measure of exposure. A 1-stop increase in exposure corresponds to doubling the amount of light reaching the sensor. For example, you can double the light reaching the sensor by changing f-stop from f/8 to f/5.6, or shutter speed from 1/500 to 1/250 sec.
The time taken for the camera's shutter to open and close. Shutter speed regulates the amount of light that impinges on the sensor or film.
Zoom racking / burst
Zoom racking or Zoom burst is a technique used for artistic photos by changing the focal length of a zoom lens during a long exposure.
A shallow DOF photo with bokeh
Camera Related Terms
Auto-exposure lock allows a photographer to meter and lock the exposure on a part of the scene and then recompose and operate the shutter release. AEL is usually activated by a button or combination of buttons on the DSLR.
Autofocus. A camera mode where the camera automatically focuses on what it believes to be the subject.
Aperture Priority (A/Av)
A semi-automatic camera operating mode in which the photographer manually sets aperture and the camera automatically sets shutter speed and ISO to achieve correct exposure.
A live view DSLR LCD with freedom of movement around one or two axis.
Contrast Detect AF. The only autofocus mechanism available in compact and mirrorless ILCs.
CDAF works on the logic that contrast is maximum when image is in focus. A camera supporting CDAF features electronics to analyze image contrast.
CDAF is considerably slower than PDAF, but is more accurate. (According to Panasonic, CDAF is 90% accurae as compared to 60% for PDAF). CDAF also allows you to more easily set the focus area.
CDAF requires Live View and is difficult to use with a DSLR (mirrorless cameras are lighter than DSLRs), or an ILC fitted with a heavy lens, unless afixed to a tripod.
Exposure Value (EV) compensation. A camera setting that shifts the calculated exposure by the set number of stops.
Electronic View Finder. Some mirrorless cameras substitute OVF with an EVF. Instead of mirror and prisms, an EVF uses secondary sensor and small LCD to project the scene to a photographer, allowing her to hold the camera to the eye.
Electronic View Finder with Interchangeable Lens. Another name for Mirrorless Camera.
Interchangeable Lens Camera. A camera that can be fitted with different lenses compatible with its lens mount.
IS / SR
Image Stabilization / Shake Reduction. It can be sensor based, as in Pentax cameras, on lens based. IS uses a gyro platform to sense motion and small motors to compensate for it, allowing shutter speed to be reduced by up to 4 stops (depending on your equipment and focal length).
Live View. The scene, as viewed by the main lens, displayed on the camera's LCD screen.
The term generally refers to an ILC without an OVF. The photographer composes using LV.
Mirrorless cameras are named as such because in the absence of an OVF there is no requirement for a mirror between the lens and the sensor. The absence of the mirror makes Mirrorless Cameras more compact than DSLRs.
The Pentax K-01 and Pentax Q7 are examples of mirrorless cameras.
Optical View Finder. An OVF uses mirror and prisms to allow the photographer to view the scene through the main lens of the camera.
Phase Detect AF. The default autofocus system of DSLRs. Most DSLRs also offer Contrast Detect AF (CDAF) associated with Live View.
PDAF uses a technique that allows near instantaneous autofocus by analyzing the distance between two images formed by two separate lenses placed behind the main lens and in front of the focusing sensor. The distance between the two focusing images is optimum when the main lens is in focus.
PDAF is also predictive when photographing a object that is moving away or towards you.
One problem with PDAF is its susceptibility to mechanical margin of error, particularly when shooting with a bright lens at small F value; at F1.4, for example.
Shutter Priority (S/Tv)
A semi-automatic camera operating mode in which the photographer manually sets shutter speed and the camera automatically sets aperture and ISO to achieve correct exposure.
Chimping is a good humored term that refers to the proclivity of photographers to immediately check every picture they shoot on their camera LCD display.
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