Glossary of Photography Terms
After writing several articles and lens reviews I found that I was referring to some photography terms that might be new to some of you. Each time I presented them I defined them so that if a new visitor to the site came in on that page they wouldn't be lost in the jargon.
I have decided now that it would be best to compile these terms onto a single page and refer to this page each time that the interesting word is used. That way each article isn't filled with a definition of word and thus getting in the way of my regular visitors.
If you are new to photography then this page may be a great introduction itself to some of the industry jargon that is used in your camera's manual or in popular photography magazines and websites.
This page is very much a work in progress
- AE-L - Auto Exposure Lock
- AI -
- AI-s -
- ASA - American Standards Association. Group that determines numerical ratings of speed for US made photosensitive products, eg. films. In 1982, its role and its influence was narrowed down by the establishment of the ISO (International Standards Organisation) and now we talk about film speed by the ISO number.
- Aperture - This term is used to refer to the hole or opening that light passes through. Specifically in photography this term refers to the size of the adjustable hole made at the back of a lens. This measurement is often referred to as an f-stop.
- Bokeh - The Japanese word Boke derived from the verb "bokase" meaning to smudge or make blurry. Pronounced BO-KEH in English. The blurry, or out of focus region behind a subject is called the bokeh. A pleasing bokeh is one which has soft, round edges to the objects. Less enjoyable bokeh is one which has harsh or sharp edges as this can be more distracting to the viewer. I describe good bokeh as smooth and creamy.
- Canon - Canon is an equipment manufacturer that produces camera bodies, lenses, and other photography equipment. Though known for high quality, items from this manufacturer are not reviewed on this site and the interested reader is urged to look to other sources for information about Canon and their product line.
- Chromatic Aberration -
- Crop - The altering of an image to change its composition by removing parts. This can be done to change the aspect ratio (like 8x10 versus 4x6), to remove unwanted or unattractive elements, or to add emphasis to a different part of the image compared to its "as shot" form.
- DC - Defocus control. Some Nikkor lenses have the ability to optical control the bokeh of the image.
- DoF - Depth of Field. This is the distance between the farthest and nearest points which are rendered in focus on an image. DoF varies according to multiple factors including lens focal length, aperture, and distance to subject.
- DSLR - An SLR camera with a digital image recording device. See SLR.
- EXIF - Exchangeable Image File. This is actually the time of image data that your camera records. When it is set to use a JPEG file for output it makes an EXIF file which is then compressed using the JPEG system.
- Emulsion - The light-sensitive part of a piece of photographic film or paper. For paper, this is normally the side with the image on it. For film, this is the non-shinny or dull side of the negative.
- Exposure - The combination of the input light intensity, f-stop, and shutter.
- Exposure Compensation - The deliberate act of obtaining a different exposure from the one that a meter (in camera or external) reads for a given input of light. This is done to create special effects or to compensate for equipment issues.
- f-stop - The ratio of the focal length of the lens to the diameter of the iris. I discuss the aperture (the iris of a lens) in further detail in my Introduction to Photography Principles and Camera Terminology article.
- Fast Lens - A lens is considered "fast" if it has a maximum aperture that lets in a lot of light. This is often a relative term as a super-long zoom that is f/5.6 would be considered fast, since it has to greatly magnify an image whereas a shorter lens would have to be f/2.8 or faster to really be considered a "fast lens." Do not confuse this with a lens that is capable of focusing quickly. While that is an admirable feature, it often has as much to do with what camera body the lens is attached to as it does the lens itself.
- Fringing - In photography fringing (often named as a certain color fringing, ex: purple fringing) is the term for an out-of-focus ghost-image created by the unique bending of light perhaps by the camera's lens, a filter, or by the design of a digital sensor itself. It is a very complex optical issue, but one can understand it best by remembering that the colors of the rainbow represent different wavelengths of light. These different wavelengths bend through glass at very slightly different angles (hence, a prism) and can result in a shift of some colors at the point where the image converges together (image sensor, or film).
- GWAC - "Guy/Gal With A Camera" - This topic has its own article.
- IF - Internal Focusing System. A system where the movement of the elements responsible for the focusing of a lens does not make the physical length of the lens change nor does it rotate any of the lens barrel. This normally decreases focus times and allows filters affixed to the end of the lens to remain in their relative positions.
- IS - Image Stabilization. This is Canon's term for what Nikon calls Vibration Reduction. See VR.
- ISO - The ISO (professionals pronounce this as "Eye Ess Oh" and not "Eye So") is a number given to film (or the digital counterpart to film, the sensor) to denote how reactive the subject is to light. A lower ISO number, for example ISO 200, requires more light than a higher ISO to render the same exposure. The comparative amount of reactivity is directly proportional to the ISO number itself. Meaning, ISO 200 requires twice as much light as ISO 400, and ISO 200 requires four times as much light as ISO 800.
- Lens Creep - A lens is said
to "creep" when it zooms or focuses by no means other
than its own weight. A lens may creep in or out as part
of it is pulled towards the earth through gravity. This
typically won't happen to lenses held perfectly horizontal.
Obviously this is a highly annoying problem with certain
This can occur in an obvious manner with the zoom of a lens going the full length in a second, or it can happen very slowly. Sometimes, if a camera is setup on a tripod gravity can slowly adjust the lens from the settings the photographer desired.
This issue is often amplified with the addition of filters on the end of the lens, a lens hood, or a ring-flash which attaches to the lens itself. All of these examples add weight to the end of a lens allowing any looseness in the lens mechanism to be more easily overtaken by gravity.
Perhaps the most famous example of this issue is the Nikon 18-200mm VR lens since it is a long zoom and is extremely loose it will easily creep on its own.
- Nikon - Nikon (pronounced
"Nye Con" and not "Ni Con") is an equipment manufacturer
based in Japan. It is known for making camera bodies
and lenses and is one of the main leading SLR/DSLR
manufacturers of US-sold cameras and lenses.
Commentary: This is the equipment that I shoot with and which you will see reviewed and referenced on this site. Selecting a camera brand is a personal decision and there is really no wrong way to go. I can share with you why I made my personal decision, but I encourage you to make yours based on your needs.
I chose Nikon for two reasons. One is that I find their sensors and lenses together render shaper images with the contrast range I'm looking for. The other is that the Nikon menus and controls make sense to me. If I had never used a camera, but knew what things did, I would put the buttons and menu options in an arrangement very similar to the designs Nikon uses. The one area that I do agree Nikon is typically lagging behind Canon is in speed. If were only shooting sports, I would sacrifice the slight picture quality (subjective view here) and menus to have a camera that takes twice as many shots per second. In sports, this feature is a major factor in getting "the shot" and would outweigh the other features.
- PC - PC, as used on this site, refers to a Perspective Control. A system where a lens is able to shift (either through bellows or a mechanical system) to alter the focal plane to thus alter the perspective of the subject. Although it could also mean "Personal Computer" that meaning is thought to be understood and will not be defined separately in the glossary.
- SLR - Single Lens Reflex
- Slow Lens - A lens is said to be a Slow Lens when its widest aperture (smallest f-stop) is not very impressive. The slowest professional lenses are typically f/2.8 with many others going f/1.8 and f/1.4 being readily available with others even going to very impressive areas such as f/1.2. Consumer lenses are slower and often their maximum aperture is nothing better than f/4 or worse, f/5.6.
- TTL - TTL stands for "Through The Lens" and is used to refer to a type of camera metering system that uses light which passes through the lens itself to judge proper exposure.
- Uncle Bob - See article on Uncle Bob.
- VR - Vibration Reduction. Nikon's term for the latest fad by camera and lens manufacturers to try and steady the image going into a camera. Most systems use a series of gyroscopes and gimbals to counter the effects of hand-shake. This technology is typically used on slow lenses since they don't let a lot of light into the camera thus requiring the shutter to stay open longer. When a shutter stays open longer any shake that may occur will have a more pronounced effect on the recorded image.
- Vignetting - This term refers to light-falloff, or a lack of even light though a lens, producing corners of an image which are darker than the center. Sometimes, especially in portraiture, this effect is purposely created (via optical or digital means) to further separate the subject from the background. The root cause of this phenomenon is that lenses actually produce a round beam of light, which is then recorded onto a square or rectangular medium.