An ongoing glossary (AOG) of incomprehensible jargon (OIJ)
(Suggestions for additions welcome.)
Aperture - The size of the iris. Bigger apertures let in more light. Bigger apertures have smaller numbers, because they are written as fractions - f/2 is bigger than f/4 on a fixed focal length lens, because if f (the focal length) is (say) 50mm , then 50/2 is bigger than 50/4. Simples! It gets less simple with zooms. Remember this- BIGGER NUMBER, BIGGER Depth of Field.
Author - The photographer who took (and may have copyright to) an image. (ie You.)
Bitmap - Same thing as a "Raster image". A picture image made up of an array of coloured dots. There are various types of bitmap image file. The .BMP file is Microsoft's own version, also called "Bitmap. Some other common bitmap file types are TIF , GIF and PNG, and JPG.
Channel - A bitmap image has three colour channels, Red, Blue and Green. JPG images are 8 bits per channel, which is just a measure of how many shades of each colour there can be. 8 bit channels have 256 shades. A 12 bit channel has 4096 shades- more bits, better colour rendition. There may be a fourth channel, containing non-colour information and making the typical JPG a 32 bit file in total. Saying "8 bit file" when you mean "8 bit per channel file" is confusing. * There is a 12 bit/channel JPGstandard, but it has yet to be widely adopted. Info here .
Compact System Camera (CSC) {See Mirrorless camera}. A mirrorless camera with interchangeable lenses. The coming thing. The bane of the DSLR , etc.
Crop frame sensor - a sensor smaller than "full frame" (36 x 24mm). Common types are APS-C and "Four-Thirds"
DPI- Digital Projected Image. (Sometimes "PDI"). A digital "slide". Usually a JPG file. Maximum size allowed in PAGB competitions is 1600 x 1200 pixels.
DSLR - Digital Single Lens Reflex. An "SLR" is a film camera (or a self-loading rifle) and the "D" was added as a selling point, so people would know not to put film in. The definitive bit of an SLR was the mirror & prism (The sticky-up bit on top) , which let you see through the lens. As digital photography matures, mirror & prism systems are being replaced by screens and digital viewfinders, so many newer digital cameras are not "SLR"s at all. Hence terms like "Bridge", "System" "Mirrorless" and so on. The day of the DSLR may already be over.
Edit in post - "In post" is movie industry shorthand for "in the post production stage" . In photography it means editing an image using software like GIMP, Lightroom or Photoshop on a computer, not in the camera. It's no different in principle to inking in (or scraping off) a wet film negative to alter a print- but it is much easier. Editing is a side of photography which either appeals or doesn't. If you enjoy messing with computers, it can be a lot of fun, especially on a dreich Winter evening. If you prefer to "get it right" in camera, that's great, but learning some basic editing won't hurt.
Electronic shutter / silent shutter. Unlike film, a sensor can be switched off. When off, it is not sensitive to light. When on, it is sensitive. So switching it on and off again after 1/100th of a second has pretty much the same effect as opening a shutter for 1/100th of a second, except it makes no noise and causes no vibration. This first appeared in compacts, which often had a simulated shutter noise . It's common in CSCs. There is a problem with "rolling shutter effect" which can distort moving subjects.
Electronic Viewfinder (EVF) - CSC / mirrorless cameras have an EVF instead of an optical viewfinder. This can display lots of information / composition gridlines and stuff. The downside is that the EVF screen is apt to have much lower resolution than the camera sensor, which can make it hard to pick precise focus.
Exposure - The amount of light to which the sensor must be "exposed" to give a desired result. Four factors decide the "correct" exposure- The aperture, the shutter interval, the ISO setting and the photographer's intent. (Most books list only the first three, which rather misses the point.)
F - There's no capital "F" in "Photography" but lower case " f " stands for the "focal Length" of a lens, which is the distance in millimetres from the front element of the lens to the camera sensor , where incoming parallel light rays will come to a focus.
FIAP- International association of photographic clubs. SPF is a member, as is any member club of SPF. (Federation Internationale d'Art Photographique.)
Full Frame - A camera sensor of 36mm x 24mm proportions, the same size as a "35mm" negative. ("35mm" movie film was 35mm wide).
GIMP- "GNU Image Manipulation Program" - (GNU stands for "GNU's Not Unix" This sort of thing passes for humour among software geeks.) GIMP is a freeware image editor, undergoing constant revision. It can do most things Photoshop does, but can be tricky to learn. Also, to edit raw files , you need a raw converter like UFRaw or RawTherapee. (This is also the case with Adobe Photoshop, but the Camera Raw converter is "built in".)
Image - A photograph, either printed or saved digitally for projection.
ISO - (Pronounced "Eye zo"). International Organisation for Standards. NOT an acronym, "ISO" is from the Greek "isos", which means "the same". There are thousands of ISO standards. The only important one for us refers to light sensitivity of camera sensors. Any sensor has a base ISO setting- usually 50, 100 or 200, which is the setting that gives the cleanest, most noise-free, unamplified images. Higher ISO settings let you take an image in lower light, but tend to be "noisier", because they have been amplified. Despite the idea of standardisation, camera manufacturers' versions of "100 ISO" can differ.
JPG - (also JPEG or JFIF. Prounced "Jaypeg") - Often misdescribed as an image file standard, this is actually a digital compression standard and dates from 1992. Competition images are usually JPG images, sized at no more than 1600 x 1200 pixels. A JPG image contains less information than a RAW file and can't be edited in quite the same way. "JPG" stands for Joint Photographers Group.
Judge - A creature of poor taste. A fellow lacking in discrimination. Alternatively, a much maligned volunteer footsoldier in the ongoing Western Front of club competition photography. More to be pitied than scolded, and surprisingly often worth listening to.
Lens - The bit that sticks out in front of a camera. Most of us think of a lens as the "Sherlock Holmes" magnifying glass. Actually, most camera "lenses" contain several glass lenses, of various shapes and glass types, mounted in such a way as to correct distortions as light passes through, so the focal length of the lens is the focal length of the whole construction, rather than of any single element.
Lightroom - An image library and editing program from Adobe. An adjunct to Photoshop, rather than a substitute.
Medium format - A sensor larger than "full frame"- 48 X 36mm in size or thereabouts (Manufacturers differ).
Mirrorless camera - A CSC / Compact System Camera. Removing the mirror and replacing the optical eyepiece with an EVF makes these cameras smaller than DSLRs and able to do more through increased computing power and electronics. Till 2018, most had crop sensors, but most major manufacturers have introduced "full frame" versions, which will probably replace both DSLRs and crop frame mirrorless cameras, as prices fall.
PAGB - Photographic alliance of Great Britain. An umbrella organisation for camera clubs.
Pixel - Short for "picture element" , the smallest point in a bitmap, or "raster" image. A dot of colour in a print or on a monitor. There is no "standard" pixel, for example it's obvious that if a full frame 36 x 24mm sensors has 20 million pixels and a 24" pc monitor has 2 million, then every pixel on the monitor must be hugely bigger than those on the sensor, which is one reason your pictures often don't look pin sharp.
Photoshop - The well known image editor produced by Adobe. Since 2016, Adobe does not sell copies of either Photoshop or Lightroom, but rents them as part of a larger suite of software, currently for about £10 a month. PS is really a tool for graphic design. For most photographers, Lightroom is probably more useful.
Prime lens - One with a fixed focal length. Not a zoom lens.
Raster image- Same thing as "bitmap"; a way to make digital images from an array of pixels.
Raw - A "raw file" is a digital image produced by a digital camera, which has not (usually) been compressed or otherwise mucked about. All camera manufacturers have their own version of raw files. There is no such thing as a .RAW file standard, as there are .TIF, .PDF or even .JPG file standards. Raw files contain all the information the camera can save in an image, so the files are bigger than compressed files like JPGs. Raw files can be 12 bit per channel , or 14 or 16, whereas a standard JPG is an 8 bit per channel image. Raw images can look rather dull, compared to JPG, as the camera software "optimises" the JPG for brightness and contrast , to give a popular sort of result, so people may feel let down when they start using raw files. There are pros and cons for both. Raw is bigger, so it is slower to save to the memory card and takes more disc space, but more versatile and much easier to edit. Ironically, while some folk feel editing is "cheating", the fact is that a Jpg image produced by a camera has already been edited, while the raw file has not. The jpg is edited by software in the camera, whereas with a raw file, you have to edit it yourself.
Shutter speed - This is not a speed. It's a time. "Shutter interval " would be better. The time it takes the shutter to open and close. 1/60th of a second is "twice as fast" as 1/30th of a second, which is gobbledegook: It's actually half as long . You couldn't make this stuff up.
SPF - Scottish Photographic Federation. The Scottish version of PAGB.
Standard lens - On a 35mm camera or a "full frame " DSLR, a 50mm lens is considered "standard" as it reproduces more or less the field of view of the human eye. On crop sensor cameras, a shorter lens would give the same effect and on medium format, a longer lens would do so. Sometimes used as a synonym for "prime lens".
Telephoto - a lens of long focal length. How long a lens has to be to be a telephoto depends on camera sensor size. A 50mm lens is a "standard" on a full frame camera, but a short telephoto on a Four Thirds system and a wide angle on a medium format.
Zoom lens - A lens with a variable focal length - eg 100-300mm. Zooms can be wide angle or telephoto, or both.