For those who love photography or those not familiar with it there's a lot of terminology that can be overwhelmingly confusing. I do my best here to offer a reference guide to what certain things mean and how they work without being too technical. If you feel like learning more on one of these topics there are plenty of resources out there that can give you incredibly in-depth explanations. This list will be updated as needed.
AF Point - An AF point is an autofocus point found within the viewfinder. These are points which the camera uses to find and lock focus.
Aperture - Aperture is the amount of light a lens lets in through the aperture ring. Each lens has it's own technical specification with an aperture range. This is denoted by f/#. For example f/1.2-22. An aperture of f/1.2 is a large aperture and lets a lot of light in. An aperture of f/22 is a small aperture and lets very little light in. Think small number, big aperture, big hole, lots of light. Large number, small hole, very little light. Aperture not only controls how much light the lens lets in, but also the depth of field. See: Depth of Field.
Aperture Priority Mode - Aperture Priority Mode on a camera is a shooting mode which lets the photographer select the desired aperture and the camera automatically sets the ISO and shutter speed to capture the correct exposure.
Automatic Mode - Automatic mode allows the user to essentially point and shoot. The camera's sensor will determine the light reading and figure out everything for the user.
Beauty Dish - A beauty dish is a type of light modifier favored by many fashion and glamour photographers. It looks like a wok and attaches to a studio strobe with the flash going through the middle. There is a plate that blocks the flash forcing all light to exit the dish in a parabolic spread. Beauty dishes typically come in a size of 18-22 inches and range in spread angles.
Black Level/Point - An adjustment in editing software that allows you to brighten or darken your blacks to true black. This allows the deepest level of black before clipping. See: Clipping.
Body - Body refers to the camera body alone, either a DSLR or SLR camera with no lens affixed.
Center-Weighted Metering - Center-weighted metering takes the immediate area around the center of the frame and evaluates the light in this region.
CF (Compact Flash) - Compact flash is a type of memory card.
Clarity - Clarity refers to the detail in an image. It is typically found in editing programs which allows a user to have an image appear softer or emphasize the details more.
Clipping - Clipping is when whites or blacks are either too white or too black that they get lost in the image. There is no more detail when whites and blacks are clipping.
Contrast - Contrast is the tonal separation in an image. Low contrast images will tend to be flat with less separation between colors. High contrast images have more separation between colors causing highlights to be brighter, shadows to be darker, and colors to generally appear more vivid.
Curtains - Curtains are the devices that drop during the shutter process that expose the sensor to light, correlating to shutter speed. The first curtain drops to expose the censor to light and the second curtain drops to stop the exposure to light. Curtains pass light from top to bottom over the censor as it records the data. At a shutter speed of 1/8000s, there is a time elapse of 0.000125 seconds between the opening (first curtain) and closing (second curtain) of the shutter. To put this into perspective, a full blink of the eye takes about 1/3 of a second, or 0.33334 seconds. The shutter at 1/8000s completes about 2,665 times faster than the blink of an eye.
Depth of Field - Depth of field refers to the amount of focal distance an image has. This is created primarily by the aperture but distance from the subject and focal length also contribute to the depth of field.
DSLR - Digital Single Lens Reflex. This is the technology and classification of a camera. Digital is pretty self explanatory. Single lens reflex is the mirror (which points up to the viewfinder) flipping up and exposing the censor to what you saw, then flipping back down.
Dump - Dumping a flash is the release of stored energy and happens either automatically or initiated by the user when the flash has been sitting at full power, causing the flash to cycle.
Dynamic Range - Dynamic range is the ability for a camera to capture full detail within light. It is the difference between the lightest light and the darkest dark that can be seen before everything disappears into a sea of white or black. Essentially it is how good the camera's eye is at seeing detail in light.
Evaluative Metering - See: Matrix/Evaluative Metering.
Exposure Triangle - The exposure triangle refers to the three components to a properly-exposed photograph: aperture, shutter speed, and ISO.
Filter - Filters are shields or apparatuses that can go over the lens to either block light or add effect.
First Curtain Sync - First curtain sync is when a flash fires when the first curtain drops, opening the shutter (or the shutter is pressed). Reference: See Curtains and Second Curtain Sync.
Flag - A flag is a device used to block light spill and help direct light.
Focal Length - Focal length is the distance in which a lens is either set (prime lenses) or is zoomed to. This is represented by the millimeter number on your lens. A 70-200mm lens zoomed in 50% would be at a 135mm focal length, where as an 85mm prime lens has a set focal length of 85mm.
F-Stop - See: Aperture.
Gel - Gels are colored pieces of film used to color lights either for color correction or added effect.
Glass - Glass is a common phrase used in place of lens or lenses. Example: Make sure you invest in the best glass you can.
Grid - Grids are used to control the directional spread of light. They prevent light spill outside of a certain angle.
Highlights - Highlights are your bright areas in an image where light hits a scene or subject.
High Speed Sync - High speed sync allows users to use flash at above the sync speed by allowing the second curtain to start closing before the first curtain is fully open. Reference: See Curtains and Sync Speed.
Histogram - A histogram in photography is a bar chart that shows the weight of exposure. More weight to the left shows more blacks, which could indicate an underexposed photograph. This will also occur with low-key photography and black backgrounds. More weight to the right shows more whites, which could indicate an overexposed photograph. This will also occur with high-key photography and white backgrounds. Histograms can be unreliable in creative environments so it is a good idea to always check the screen and preview what you are taking to ensure it is to your liking.
Hue - Hue is the color spectrum within an image.
Inverse Square Law - This is the mathematical equation of light falloff, or how light fades the further it travels. The formula for this is: Intensity = 1/Distance².
ISO - ISO is a number used to gauge a camera sensor's sensitivity to light. The lower the number, 100, the less sensitive to light, and the higher the number 3200, the more sensitive to light. Lower ISO will give you less grain and noise in a photo while a higher ISO will add more grain and noise. ISO stands for International Standards Organization and is an industry standardized numerical system. At ISO 800 you are letting in three times more light than you are at ISO 100. This is figured by halves. ISO 800 is double ISO 400 which is double ISO 200 which is ISO 100. So, 100 to 200 to 400 to 800 is three steps of movement and you have adjusted your exposure by three full stops.
JPG/JPEG - JPG is a file type for a finished image. When you shoot JPG in camera the camera's sensor collects all the data it sees, processes the image, and throws out whatever data it didn't use. JPG images typically have very little room for editing changes due to the destruction of data. File sizes will range from 1-6 Megabytes per file. Reference: See RAW.
Kelvin - Kelvin is a unit on a color temperature scale. Natural daylight is said to be between 5,400-5,600 K (Kelvin)
Light Modifier - A light modifier is any apparatus used to modify a light source. This could be something as simple as a diffusion panel or items such as umbrellas, beauty dishes, reflectors, softboxes, grids, etc.
Lightroom (Adobe) - Lightroom is a product by Adobe that offers the fundamentals of Adobe Photoshop in an easier, more simplified slider system.
Macro - Macro, either lens or photography, is a reference to extreme small scale. Macro lenses are able to capture incredible detail at very close focal lengths.
Manual Mode - Manual mode is where the user inputs all their settings manually to ensure a proper exposure. Manual mode can dive extremely deep depending on how technical you are and comfortable you are navigating the menu systems.
Matrix/Evaluative Metering - Matrix metering takes the entire frame, splits it into regions, and averages all these regions together to evaluate the light.
Metering - Metering is the evaluation of light to determine proper exposure. There are three different types of metering on DSLR cameras: Matrix/Evaluative Metering, Center-Weighted Metering, and Spot Metering. Reference: See Matrix/Evaluative Metering, Center-Weighted Metering, and Spot Metering.
Mirrorless - A mirrorless camera differs from an SLR system due to the fact that there is no mirror. Light passes through the lens directly onto the image sensor. These cameras are smaller and lighter than an SLR system.
Neutral Density (ND) Filter - A ND filter restricts light of all wavelengths coming into the camera so as to not have any shift in the hue of an image. A graduated ND filter will have a gradient to it allowing one to block out just the sky or a certain region of a photograph where light is more intense.
Off Camera Flash (OCF) - Off camera flash is just as it sounds, flash heads that are off the camera and fired with remote triggers allowing you to have advanced and more creative lighting setups.
Photoshop (Adobe) - Photoshop is a program by Adobe that allows both basic and advanced editing.
Preset - A saved group of settings in editing software to make a one-click base edit.
Prime Lens - A prime lens is one which does not zoom. It has a set focal length. These lenses are great for landscapes, portraiture, and product photography and typically have great dynamic range. Common examples are 24mm, 35mm, 50mm, and 85mm. More specialty prime lenses can include tilt/shift lenses and fisheye lenses.
RAW - RAW is a file type that is essentially a digital negative. When you shoot RAW in camera the camera's sensor collects all the data it sees and saves it, giving you a picture as a preview. The data in the image is usually stored to a flat curve so editing is required to bring images back to life. RAW images have a great deal of editing fluctuation since all the data is still there. File sizes will range from 18-100+ Megabytes per file. Reference: See JPG/JPEG.
RAW+JPG - This is a setting within the file type menus that allows the camera to record both a RAW and JPG image simultaneously. Reference: See RAW and JPG/JPEG.
Ring Flash - A ring flash is a circular flash that typically goes around the end of the barrel of a lens.
Rule of Thirds - The rule of thirds is a fundamental composition concept. You divide your view into a grid with a line at the first third and second third both on a horizontal and vertical axis, making 9 smaller rectangles within your view.
Saturation - Saturation is the intensity of color in an image.
SD (Secure Digital) - SD is a type of memory card.
Second Curtain Sync - Second curtain sync is when a flash fires before the second curtain drops, closing the shutter. Reference: See Curtains and Second Curtain Sync.
Shoe - A shoe is a mounting socket commonly used for audio, lighting, and triggering systems. A hot shoe is one that is powered or has the ability to pass information, whereas a cold shoe is purely a mounting socket and any device on it needs to have its own power and communication source.
Shutter Speed - Shutter speed is how long the camera allows light to enter the camera and hit the sensor. The typical range of (most) cameras is 1/8000 second to over 10 minutes.
Slave - Slave mode is where a flash uses an optical sensor to see another flash go off in order to trigger itself.
SLR - Single Lens Reflex. This is the technology and classification of a camera. Typically film, single lens reflex is the mirror (which points up to the viewfinder) flipping up and exposing the censor to what you saw, then flipping back down.
Softbox - A softbox is a light modifier used to help control light more-so than an umbrella, which allows light spill and shadows if not used properly. Softboxes contain an opaque black shell which the light source is inserted through a hole in the back. The inside of the shell has a reflective surface that looks like the shiny side of aluminum foil. The front of the softbox has a white diffusion panel to soften the light.
Specular Highlights - Specular highlights are bright spots in a photo that cause a shine.
Speedlite - Speedlites are portable, battery-operated flash units that can be mounted to hot or cold shoes.
Spot Metering - Spot metering takes only into account the selected AF point and evaluates the light around this region.
Strobe - A strobe is a high-power flash head that can operate either by battery or plugged into a wall. They are commonly used with light modifiers. Reference: See Light Modifier.
Sync Speed - Sync speed is the speed at which a camera can capture a complete flash duration from a flash unit between the first and second curtains. Without high speed sync and above the sync speed, the user will experience either only partial light or black bars crossing the image as as the curtains close, caused by only partial exposure of light to the sensor.
Telephoto Lens - Telephoto lenses (and super telephoto) have long focal lengths and the ability to optically zoom into long range subjects. They tend to be very heavy due to the amount of glass in them.
Trigger - Triggers are radio remote systems for off camera flashes. These send a signal from either the transmitter or transceiver when the shutter is pressed to the receivers hooked up to speedlites and strobe heads causing them to fire.
Watt-seconds - Watt-seconds is the measurement of energy capacity that is storable within a flash unit.
White Balance - White balance is the point at which pure white is set. This dictates both the whites in your image but also sets the color temperature of the image.
White Level/Point - An adjustment in editing software that allows you to brighten or darken your whites to true white. This allows the brightest level of white before clipping. See: Clipping.
Wide Angle Lens - Wide angle lenses typically do not surpass 50mm in focal length. They range from approximately 8mm to 50mm.
Zoom Lens - A zoom lens is one that has the capability to zoom optically.