Joshua Cripps’ Photo Blog

This page is under construction but should be updated soon

This page is currently under construction, but will be updated soon.

Confused by some verbiage somewhere?  Check out all the terms below to get things cleared up.

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Amp Glow

The added noise in a photo (usually large, red discolored blobs) due to excessive heat generated by long camera usage.  Usually seen in long exposures at night.

Aperture

The diaphragm in your camera’s lens which allows light to enter the camera.  Changing the size of the aperture will change the depth of field (DOF) of a scene as seen by the camera: a smaller aperture will result in a deeper DOF; a larger aperture will create a shallower DOF.  Aperture is represented by an f-number or f-stop, which is displayed on the camera as f4, f8, f11, etc.  A factor of two change in the f-stop represents a factor of four change in the aperture size, which is equivalent to a 2-stop change in exposure.  For example, with all other settings the same, a photo taken at f/4 is four times brighter (two stops = 2^2 = 4) than one at f/8.

Aperture Priority Mode

A control mode on a camera where the user sets the desired aperture and the camera adjusts shutter speed accordingly in order to maintain the correct exposure.  Useful in situations where depth of field is the most important consideration.

Auto-Focus

When the camera focuses the lens automatically.

Barrel Distortion

Distortion caused by a lens such that lines which should be straight in a photo appear to bow out away from the center of the image.

Blown-Out

When the highlights, or brightest parts of an image, become so bright they are shown as completely white.

Body

The camera itself.  I.e. the part with all the controls, displays, and viewfinder.

Bokeh

The out-of-focus area of a photograph and its aesthetic quality.  Generally, smoother, rounder, and softer bokeh is considered better.

Bracketing

Bracketing is the process of shooting multiple images of the same scene while varying one parameter from shot to shot in order to select the best photo after the fact.  Exposure is the most common parameter to be adjusted while bracketing (usually done by varying the shutter speed).  Exposure bracketing is very useful for digital blending and High Dynamic Range (HDR) processing.  Bracketing is not limited to exposure however, as one can bracket white balance, shutter speed, aperture, or focus as well.

Center-Weighted Metering

Using the central portion of the camera’s light sensor as the control point for determining exposure.  Many cameras have a setting to adjust how large this center-weighted area is.

Chromatic Aberration (CA)

Also known as fringing, chromatic aberration is the effect caused by different wavelengths of light refracting differently in the glass of a lens.  Often seen as magenta or cyan halos in areas of high contrast in photos, CA is generally more of a problem for zoom lenses rather than prime lenses.

Circle of Confusion

A physical dimension above which point-sources of light degrade into circles due to being out of focus.  In other words, the acceptable limit of sharp focus.

Composition

The layout, placement, angle, and perspective of a scene within an image.

Continuous Focus

A version of auto focus where the camera continuously focuses the lens as the distance between the camera and the subject changes.

Crop Factor

The relative size of a camera’s image sensor compared to a full-frame sensor or 35 mm slide.  Most digital SLRs are a 1.5 or 1.6 crop factor, meaning their sensors are 1.5 or 1.6 times smaller than a full frame sensor.  This has the added effect of increasing the relative focal length of lenses on cropped-sensor cameras. For example, an image which covers the entire sensor on a cropped camera will only cover 2/3 of the sensor on a full frame camera.  In order for the image to cover the entire full-frame sensor, the camera lens would need to be zoomed in 1.5 times farther.  Therefore, a 200 mm lens on a cropped-sensor is approximately equivalent to a 300 mm lens on a full-frame sensor.

Depth of Field

The term which describes how deep focus runs in an image.  Images with a shallow depth of field have very limited areas in focus whereas images with a deep depth of field can be in focus from front to back.

Digital Blending

See Digital Graduated Neutral Density Filter.

Digital Graduated Neutral Density Filter

A digital blend between two or more exposures of the same scene in a way to compress the dynamic range of the scene.  Mimics the effect of a Graduated Neutral Density filter.

Dynamic Range

The range of brightness values in a photograph or scene, ranging from pure black to pure white ( i.e. very dark shadows and very bright highlights).  Nature scenes often have a dynamic range  greater than that a camera can capture, necessitating the use of filters or digital processing techniques in order to compress the dynamic range of the scene to a capturable level.

EXIF

Data recorded by the camera and viewable with most image-viewing software which gives the camera settings (such as shutter-speed, f-number, ISO, white-balance, flash settings, etc.)  for any given image.

Exposure

How bright or dark a photo appears.

Exposure Compensation

Manually overriding the camera’s default exposure setting in order to purposefully render an image brighter or darker than it would be by default.

F-number

The indicator of the aperture setting on a camera.  Larger f-numbers indicate smaller aperture sizes.  The relationship between f-numbers and aperture is such: when the f-number doubles, the aperture size decreases by a factor of four.  For example, at f/8, the aperture is four times larger than at f/16.

F-stop

See F-Number

Fast

An adjective which describes a lens with a relatively wide maximum aperture.  For example:  f/2.8

Fill Flash

Flash that is used to fill in deep shadows in backlit subjects.  Fill flash can also be used to brighten a dark foreground in scenes with a high-dynamic range.

Film

I have no idea what this is.

Filter

A thin piece of clear, colored, or darkened resin or glass which attaches to a lens in order to modify the light entering the lens by colorizing it, darkening it, etc.

Focal Length

An attribute of lens generally used as an indication of how wide a field of view the lens has.  Smaller focal lengths are used for wider lenses.  For example, a wide-angle lens with a focal length of 12 mm has a field of view of around 100 degrees, whereas a telephoto lens at 200 mm might only have a field of view of 12 degrees.  In practical terms, this means the 200 mm lens is much farther “zoomed in” than the 12 mm lens.

Focus Point

Seen when looking through a camera’s viewfinder, a focus point is a selectable rectangle the camera will use as a control point when determining what to focus on.

Frame

1) As a verb, frame means to compose an image: e.g. “Do you like how I framed this shot?”

2) As a noun, frame means the area seen through the viewfinder and captured by the image sensor: e.g.  “If I stand here will I be in your frame?”

3) Frame can also simply mean a photo: e.g. “I went out shooting tonight and shot 300 frames.”

Fringing

See Chromatic Aberration

Full-Frame

Can refer to an image sensor or a camera with an image sensor which is the same size as a 35-mm piece of film.  In contrast to most digital SLRs which have image sensors 1.5 or 1.6 times smaller than 35 mm.  The larger sensors give higher image quality and less noise and are therefore generally found in “pro-level” digital SLRs.

Glass

Another word for a lens.  E.g. “Wow, that’s a nice piece of glass you’ve got there.”

Graduated Neutral Density Filter

A colorless filter which is dark on one half and clear on the other half.  These filters are used in scenes with high dynamic range in order to compress the dynamic range to something the camera can capture.  For example, by placing the dark part of the filter over the sky (as seen by the camera), a photographer can make the sky 2 or 3 stops darker while leaving the brightness of the foreground unaffected.

High Dynamic Range

1) A dynamic range greater than that the camera can capture.  For example, a scene which contains a full range of brightness values from very dark shadows to very bright highlights has a high dynamic range.

2) High Dynamic Range can also refer to a specific type of digital processing in which multiple exposures of the same scene are captured through exposure bracketing and combined via specialized software in order to display the maximum amount of detail in both the shadows and highlights in an image.

Highlights

The brightest parts of an image.  If the highlights are so bright that they are rendered as completely white, they contain no detail and are said to be “blown-out.”

Histogram

A graphical display of the range of brightness values in an image.  The histogram indicates if an image is too dark or too bright, or has excessive shadows or excessive highlights.

Hyperfocal Distance

Hyperfocal distance can be thought of as the distance where you should focus your camera so that you get maximum depth of field.  More technically, it’s defined as the point where if you are focused there, your scene will be in acceptably sharp focus from half that distance to infinity.  Hyperfocal distance changes based on focal length and aperture according to the formula: H = L^2 / (c * F) + L, where L is focal length, F is f-number, and c is the acceptable limit of sharp focus (0.03 mm is a typical value).

ISO

The setting on your camera which indicates how sensitive to incoming light.  Lower ISOs mean the camera is less sensitive.  Higher ISOs allow for fast shutter speeds in low light, but shooting at high ISO introduces more noise into an image.  The relationship between ISO values is straightforward: for example, ISO 200 is twice as sensitive as ISO 100.  ISO 400 is four times less sensitive than ISO 1600.

Long Lens

See Telephoto Lens

Long-Exposure

A term used to describe photos which have a shutter speed much longer than a fraction of a second.  While there is no hard limit as to what is “long exposure” and what isn’t, long exposure photo generally have shutter speeds ranging from a few seconds, to a few minutes, to a few hours.  This allows for the capture of stars trails, moving car lights, the motion of clouds, and perfectly smooth and uniform water, among other things.

Macro Lens

A lens generally used for taking extreme close-ups of small subjects, such as insects or flowers.

Manual Focus

A method of focus where focus is selected manually by the photographer.

Manual Mode

A control mode on a camera where the user sets the aperture, the shutter speed, and ISO value.  The camera will not compensate for any user settings.  Useful in situations when you want absolute control over all aspects of a photo.

Matrix Metering

Using an array of points from all over the camera’s image sensor in order to determine proper exposure for a scene.  Gives an averaged value for exposure and prevents large changes in exposure if the camera’s focus point moves from something dark to something bright.

Megapixel

A standard measure of camera resolution.

Monopod

A support for a camera made of one single leg.  Helps remove camera shake and jitter but allows camera to pan and rotate quickly.  Useful for photography of fast-moving subjects using long lenses, such as sports or wildlife photography.

Neutral Density Filter

A dark filter with completely neutral color designed to cut the amount of incoming light entering a camera.  Useful for increasing shutterspeed.

Noise

Also known as “grain,” noise is tiny discolored dots in a photo which can destroy detail and prevent color gradations from looking smooth.  Noise is caused by shooting at high ISOs, shooting in low-light conditions, using long-exposures, and post-processing images.

Pincushion Distortion

Distortion caused by a lens such that lines which should be straight in a photo appear to bow in towards the center of the image.

Point and Shoot Camera

Your typical pocket-sized digital camera.

Polarizing Filter

A filter designed to polarize the light entering a camera in order to cut haze, reflections, help color saturation, and make the sky a richer blue.  Polarizers work best when shooting 90 degrees off-axis from the sun.

Prime Lens

A lens with a fixed focal length.  Because the optics are optimized for one focal length, prime lenses are generally sharper, clearer, and possess less distortion than zoom lenses.

Reciprocity Failure

A given exposure can generally be obtained through many combinations of aperture and shutter speed.  For example, a shutter speed of 1/100 at f/8 will give the same exposure as 1/200 at f/5.6 and 1/400 at f/4.  This is called reciprocity. However, in low light situations this reciprocal relationship between shutter speed and aperture breaks down.  This is reciprocity failure, and must be compensated for by increasing shutter speed for a given aperture past what this relationship would normally dictate.

Sensor

The actual light-recording part of the camera.  The digital analog to a piece of film.

Shadows

The darkest parts of a photo.  Shadows so dark they are shown as pure black in an image contain no detail and can be said to be “lost.”

Sharp

Sharp means in focus.  The sharper an image is, the more fine detail can be seen in it.

Shutter Priority Mode

A control mode on a camera where the user selects a desired shutter-speed and camera compensates by changing aperture in order to maintain exposure.  Useful in situations where shutter speed is the most important consideration, such as panning shots.

Shutter Speed

An indicator of how long your camera’s shutter is open when you press the shutter button.

Single Focus

A method of auto-focus where the camera focuses on the subject and maintains focus at that distance even if the subject moves.

Single Lens Reflex (SLR Camera)

A camera designed so that the photographer looks out through the camera lens and sees the scene exactly as it is captured by the camera.  Can be used with interchangeable lenses.

Soft

When something that should be in focus is slightly out of focus, it is said to be soft.  E.g. “These rocks in the foreground look a little soft, I wish they were in sharper focus.”

Spot Metering

A method of using the camera’s current focus point as the control point for determining exposure.

Stop

A change in exposure by a factor of two.  I.e. a photo that is twice as bright as another photo is 1 stop brighter.  A photo that is four times brighter is 2 stops brighter.

Stop Down

To increase the f-number in order to increase depth of field or improve lens performance.

Telephoto Lens

A lens designed for taking pictures of far-away subjects or for magnified shots of near subjects.  Some telephoto lenses can also be used as macro lenses.

Tones

The color and brightness of an image.

Tripod

A stabilizing support for a camera which has three legs and a head to which the camera is mounted.

UV Filter

A completely clear filter which is often screwed onto the front of a lens in order to protect the actual lens glass from damage and contamination.

Viewfinder

The part of the camera that the photographer looks through in order to compose an image.

Vignetting

The gradual darkening of an image near the edges of the image.  Vignetting can be caused by physical objects, as well as the optics within a lens.  While generally undesirable in landscape photography, vignetting can be used to great effect in wildlife and portrait photograph by drawing the viewer’s attention to the subject at the center of the photo.

Wide Angle Distortion

A shift in perspective caused by wide angle lenses such that objects become stretched as the near the edge of the field of view of the lens.  For example, a  spherical ball viewed through a wide angle lens can appear elliptical if it’s near the edge of the field of view of the lens.

Wide Angle Lens

A lens designed to have a very wide field of view.  Very useful in landscape photography.

Wide Open

When a lens is set to its maximum aperture (smallest f-number), it is said to be wide open.

Zoom Lens

A lens which can transition through a range of focal lengths in order to provide a great number of options for composition.

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Any terms I’m missing?  Any you want described?  Leave a comment or send me an email.

Light Loss.

Blueing of photos.

This page is under construction.

This page is currently under construction

This Page is under construction