Everyone who takes a deeper dive into photography for the first time, gets drowned by a flood of strange terms and abbreviations. Test reviews, tutorials, and online communities are just full of them. What confused me even more in the beginning, was the fact that there is often more than one designation for the same thing – or, vice versa, one and the same shortcut has several different meanings. I am currently replacing some of my gear, so I had to make sure I was adding the correct designations to the respective item descriptions. And since I was at it anyway, I’m writing it down here for future reference – yours, as well as mine.
Photography fills an abundance of books and videos, which describe the basic steps, give instructions, and explain the terminology. I do not intend to compete with that. However, I do want to give an explanation in my own words of the terms I am using regularly in my blog posts.
For most of the terms, I have added links to the respective articles on Wikipedia, in case you want to read more about a certain topic. And if you’re interested in all the details, I highly recommend Mark Levoy’s “Lectures on Digital Photography”.
From a technical point of view, the aperture is the opening in the lens through which light hits the sensor. Usually, it can be varied in size (⇒ Wikipedia).
From an artistic point of view, the aperture is the most important tool for creating an image. It controls the depth of field, i.e. the distance range that will be shown sharp in the picture. This makes the difference between a portrait with a soft background, and a landscape photo where the entire frame is in focus. It also influences the amount of light passing through the lens, in particular when using a flash.
The term is derived from the Japanese word for “blurred”. In photography, it describes the quality of the out-of-focus areas in a picture taken with a wide-open aperture (⇒ Wikipedia). The bokeh depends on the construction of the respective lens, and the quality of the individual lenses it is comprised of. In particular, portrait lenses usually produce a nice bokeh, to create smooth backgrounds that do not distract in any way from the subject. There are, however, lenses that produce a rather fidgety bokeh, for instance because contours get doubled in out-of-focus areas.
|Chromatic Aberration /
When light passes through drops of water, the individual colors are refracted differently. Sunlight gets split into its individual colors, which we see as a rainbow. The same happens when light passes through pieces of glass in a lens. This means the individual lenses need to be tuned in a very specific way to ensure that on the camera sensor, all the different colors match up again in the intended way. Where this fails, green and purple color fringes appear on contrasting edges in the image, for instance at branches of a tree against a bright sky, or the white frame of an otherwise dark window (⇒ Wikipedia). Chromatic aberration can be corrected in many image-processing software tools, such as Adobe Lightroom.
To be able to compare different camera types, the main parameters such as the focal length are always converted to the so-called full-frame format. This designation applies to cameras with a sensor the same size as a negative of a 35 mm miniature film (24 x 36 mm). The crop factor equals the ratio of the length of the diagonals (⇒ Wikipedia).
|Depth of Field||
Depth of field refers to the distance range, within which objects are shown sufficiently sharp in the image (⇒ Wikipedia).
Illustrates the correlation of shutter speed, aperture, and ISO setting for the correct exposure of an image.
|Exposure Time /
The time interval during which light hits the sensor. Most cameras allow adjustment between 1/4,000th of a second and 30 seconds (⇒ Wikipedia).
|Flash Sync Speed||Identifies the shortest exposure time at which a flash without special ‘high speed’ capability will render a fully exposed image. This depends on the build of the shutter (see below), but with most cameras, it is around 1/200th of a second.|
|Internal Focus||On a lens with internal focusing, all moving elements for focusing on your subject are inside the lens. This means that in particular the front element of the lens does neither extend nor rotate when focusing. This is important when using filters that depend on the correct orientation to get the desired effect, such as polarizing filters or graduated filters.|
The name of the International Organization for Standardization in Switzerland. As the shortcut for this organization would be different in every language (in English, it should actually be IOS), ISO is used as a proper name. It is derived from the Greek syllable “iso”, meaning “equal”. In photography, the ISO value describes how sensitive an analog film or digital sensor is to light, as defined in the standard ISO 5800 (⇒ Wikipedia).
|Minimum Focus Distance||
The minimum focus distance is the shortest distance on which the camera can still focus with the respective lens. It is important to know that this distance is always measured from the sensor, and not from the front element of the lens. The position of the sensor is marked by a symbol (
The shutter is a mechanism inside the camera that allows light to hit the sensor only for the chosen exposure time (⇒ Wikipedia). There are two main types of shutters:
There are an almost infinite amount of abbreviations in photography. I have selected the ones I often use myself. This section leaves aside all abbreviations that designate lens characteristics; you will find those below in a table of their own.
Auto-focus – The system your camera uses to focus on the targeted subject. There are two distinctly different auto-focus systems: Phase detection is what single-lens reflex cameras employ when using the optical viewfinder. Edge detection is applied when looking through an electronic viewfinder or using the display, for instance on a cell phone. Phase detection is faster, while edge detection is more reliable. In addition, depending on your camera and lens, there are different types of drives moving the lenses accordingly; also see the lens designations below.
Advanced Photo Systems-Classic – This designation embraces digital cameras with a sensor size between 22.5 x 15.0 mm (crop factor 1.6) and 25.1 x 16.7 mm (crop factor 1.5). Basically all interchangeable lens cameras with a retail price under 1,000 € have such a sensor. APS-C is not a standardized label; the actual sensor size varies between manufacturers. Nikon calls their APS-C cameras “DX”.
The designation goes back to the APS system, which was invented back in the 1990s for analog film. The image size is about ⅓ of a 35 mm miniature film. This made it possible to build much smaller cameras, and to store additional information on the film. Due to the quickly emerging digital photography, however, APS never became accepted for analog film, and quickly vanished again.
APS-C as a classification of the sensor size is not related to the camera sensor technology APS (Active Pixel Sensor). This is a type of so-called CMOS sensor, which, due to their compact build and low energy consumption, are used in almost all cell phones and compact cameras.
|ILC||Interchangeable Lens Camera – A camera where you can quickly change the lens. Often used as a generic term for mirrorless or single-lens reflex cameras, to distinguish them from compact cameras with a built-in lens.|
|DSLM||Digital Single-Lens Mirrorless – Digital cameras without optical viewfinder. They are often also referred to a System Cameras (Example: Sony Alpha a6000). “Single-Lens” means that the image in the viewfinder is captured through the same lens as the actual photo. On older compact cameras, the viewfinder often had its own optics. Nowadays, basically all cameras are digital, the D is often omitted and just SLM is being used. In addition, there are several synonymous acronyms: MILC (Mirrorless Interchangeable Lens Camera), MSC (Mirrorless System Camers) and – my favorite – EVIL (Electronic Viewfinder Interchangeable Lens camera).|
|DSLR||Digital Single-Lens Reflex – Digital cameras with an optical viewfinder that uses the same lens as the image sensor (Example: Canon EOS 760D). Again, the D is often omitted and just SLR is used.|
|MF||Manual Focus – Interchangeable lenses usually allow for manually focusing on your subject. This is meaningful in difficult lighting conditions, e.g. for night photography, or for pictures where a moving object shall be captured in a certain position and the auto-focus wouldn’t be fast enough.|
Micro-Four-Thirds – A sensor format with crop factor 2, used primarily by Olympus and Panasonic. “Four Thirds” relates to the 4:3 aspect ratio of the sensor, in contrast to the otherwise usually 3:2.
Straight Out Of Camera – This abbreviation is mostly used in online forums and photo communities, and means that the picture it refers to has not been post-processed on a computer in any way.
Acronyms on lenses tend to be especially confusing, because the manufacturers use different labels for the same functionalities and characteristics. The table below summarizes the most prevalent shortcuts for the brands I use.
I have left out all terms related to the ‘optical formula’ of a lens, i.e., which specially shaped lenses are built in, and which specific coatings they have. This would go far beyond the scope of this post. In the end, all that matters it their effect on the image quality (distortion, flaring, and chromatic aberration).
|Lens for Full-frame Cameras||EF||DG||Di||FX|
|Lens for Cameras with APS-C Sensor||EF-S||CS||DC||Di II||DX|
|Lens for mirrorless Cameras||EF-M||FE (Sony E-Mount)||DN|
|Image Stabilizer||IS (Image Stabilization)||OS (Optical Stabilizer)||VC (Vibration Compensation)|
|Auto-focus||USM (Ultra-Sonic Motor)
STM (Stepping Motor)
|AF||HSM (Hyper-Sonic Motor)||USD (Ultrasonic Silent Drive)||AF|
|Professional Lens||L (Luxury)||A (Art)
|SP (Super Professional)||AT-X Pro|
|Consumer Lenses||C (Contemporary)||AT-X|
- Canon: Lenses with internal focus, as well as consumer lenses, do not have a dedicated designation.
- Samyang: Lenses from Samyang are sold under several different brands, including Rokinon, Bower, Opteka, Pro-Optic, Vivitar und Walimex. They are technically identical, but their prices vary drastically. Full-frame lenses do not have a special label. No lenses with image stabilization are available. Finally, Samyang does not distinguish between different product lines.
- Tamron: As far as I know, Tamron does not offer any lenses for mirrorless cameras. Consumer lenses do not have a specific label.
- Tokina: There are no lenses available with image stabilization, or for mirrorless cameras.
Recommendation: When you get started, all those terms and abbreviations seem rather confusing. But don’t let yourself be scared by that! To learn the basic terms in the beginning, a book can really help; but in the end, it’s ‘learning by doing’. In particular, the exposure triangle needs closer attention, and you’ll need to memorize the creative possibilities (How do I blur the background? How do I freeze motion?).
What I’ve learned: A lot 😀 And I’m still learning. Even writing this article helped me to better understand a number of things…
In addition to the Wikipedia links, additional information can be found here:
- Download: Photo Cheatcard for Photographers
- Dave Morrow: Exposure Triangle Photography Guide
- SLR Lounge: Understanding Exposure With The Exposure Triangle (YouTube)
- Tony Northrup: Aperture, Shutter Speed, ISO, & Light Explained (YouTube)
- Mark Levoy: Lectures on Digital Photography
- Tony Northrup: Stunning Digital Photography
- The Slow Mo Guys: Inside a Camera at 10.000fps (YouTube)
- Robert Hall: Electronic Shutter vs Mechanical Shutter in Mirrorless Cameras (YouTube)
- What do all those cryptic number and letter codes in a lens name mean? (photo.stackexchange.com)
Picture credits: Title image: own graphic.