This cheatsheet defines the photography terms you meet most often, in one or two plain sentences each, grouped by subject so related words sit together. Each linked term opens a full guide. For an A to Z list of every term on the site, use the photography glossary.
If you only learn ten words, learn these: aperture, shutter speed, ISO, exposure, stop, focal length, depth of field, white balance, RAW and composition. Almost every tutorial, camera menu and lens description is built from them.
Exposure Terms
Exposure is how much light reaches the sensor. These words describe how you control it and how you judge it.
- Exposure: The total amount of light that reaches the sensor while a photo is taken, which decides how bright or dark the image is. It is set by aperture, shutter speed and ISO together.
- Aperture: The adjustable opening inside the lens that lets light through. A wider aperture lets in more light and gives shallower depth of field.
- F-stop (f-number): The number that describes aperture size, written f/2.8, f/8, f/16 and so on. It is the focal length divided by the opening’s diameter, so a smaller number means a wider opening.
- Shutter speed: How long the sensor is exposed to light, written in seconds or fractions of a second (1/1000, 1/60, 2″). Fast speeds freeze motion; slow speeds blur it.
- ISO: How strongly the camera amplifies the signal from the sensor. Low ISO (100) gives the cleanest image; high ISO (3200 and up) brightens the image in dim light but adds noise.
- Exposure triangle: The idea that aperture, shutter speed and ISO all change brightness, so changing one means adjusting another to keep the same exposure. Each also has a side effect: depth of field, motion blur or noise.
- Stop: A doubling or halving of light. Going from 1/125 to 1/250, from f/4 to f/5.6, or from ISO 400 to ISO 200 each cuts the light by one stop.
- Exposure value (EV): A single number for any combination of aperture and shutter speed that gives the same exposure. One EV equals one stop.
- Metering: How the camera measures scene brightness to suggest settings. The common modes are evaluative (matrix), center-weighted and spot.
- Middle gray: The mid-tone a light meter assumes every scene averages to, usually described as 18 percent reflectance. It is why meters underexpose snow and overexpose black subjects.
- Exposure compensation: A control that tells an automatic mode to make the picture brighter or darker than the meter suggests, in stops (+1, minus 2/3 and so on).
- Exposure lock (AE-L): A button that holds the current exposure so you can meter one part of the scene and then recompose.
- Histogram: A graph of the tones in an image from black on the left to white on the right. It is the most reliable way to check exposure on the camera.
- Clipping: Detail lost because tones are pushed to pure white (blown highlights) or pure black (crushed shadows). It shows as a spike against either edge of the histogram.
- Overexposure and underexposure: An image that received too much light (too bright, highlights lost) or too little (too dark, shadows noisy).
- Dynamic range: The span from the darkest to the brightest tones a sensor can record with detail in a single exposure, usually given in stops.
- Bracketing: Taking several frames of the same scene at different exposures, usually a stop or more apart, to make sure one is right or to blend them later.
- Expose to the right (ETTR): Exposing as brightly as possible without clipping highlights, then darkening in editing, to get cleaner shadows.
- Sunny 16 rule: In bright sun, f/16 with a shutter speed of 1 over your ISO (for example 1/100 at ISO 100) gives a correct exposure without a meter.
Camera Modes and Controls
- Shooting modes: The settings on the mode dial that decide how much of the exposure you control: Auto, Program (P), Aperture Priority, Shutter Priority and Manual.
- Manual mode (M): You set aperture, shutter speed and ISO yourself. The meter only advises.
- Aperture Priority (A or Av): You choose the aperture and the camera picks the shutter speed. The most used mode for general shooting.
- Shutter Priority (S or Tv): You choose the shutter speed and the camera picks the aperture. Useful for action.
- Auto ISO: The camera raises or lowers ISO to keep the exposure right, often within limits you set. It pairs well with Manual mode for moving subjects.
- Burst mode (continuous drive): Holding the shutter button takes frame after frame, measured in frames per second.
- White balance: A setting that corrects the color of the light so white objects look white. Presets include Daylight, Cloudy, Shade and Tungsten, or you can set a Kelvin value.
- EXIF data: The settings, date and camera information stored inside each image file.
Focus and Sharpness Terms
- Depth of field: The zone in front of and behind the focus point that looks acceptably sharp. Wide apertures, long lenses and close subjects make it shallower.
- Shallow depth of field: A thin zone of sharpness that isolates the subject against a blurred background, a common portrait look.
- Bokeh: The look of the out-of-focus areas of a photo: smooth or busy, round highlights or harsh ones.
- Autofocus (AF): The camera focuses the lens for you. Single AF locks focus once for still subjects; continuous AF keeps adjusting for moving subjects.
- Focus points: The spots or zones in the frame where the camera can focus. You can let the camera choose or pick one yourself.
- Back-button focus: Moving the autofocus start from the shutter button to a button on the back, so focusing and taking the picture are separate actions.
- Manual focus (MF): Turning the focus ring yourself. Useful in the dark, in macro work and when autofocus keeps picking the wrong subject.
- Hyperfocal distance: The focus distance that gives the most depth of field at a given aperture and focal length. Everything from half that distance to infinity looks sharp.
- Motion blur: Blur from the subject or the camera moving during the exposure, either a mistake or a deliberate effect.
- Hand-holding rule: A starting guide that your shutter speed should be at least 1 over the effective focal length (1/50 for a 50mm lens on full frame) to avoid blur from shaky hands.
- Image stabilization: A mechanism in the lens or the camera body that counteracts hand shake, allowing sharp handheld shots at slower shutter speeds. It does not stop subject motion.
Lens Terms
- Focal length: The number in millimeters on a lens (24mm, 50mm, 200mm). It sets the angle of view and magnification: shorter is wider, longer is closer.
- Angle of view: How much of the scene the lens takes in, measured in degrees. It depends on both focal length and sensor size.
- Wide-angle lens: Shorter than about 35mm on full frame. Takes in a broad view and exaggerates the distance between near and far objects.
- Normal lens: Around 40mm to 50mm on full frame, giving a view close to how a scene feels to the eye.
- Telephoto lens: Longer than about 70mm on full frame. Magnifies distant subjects and appears to compress distance.
- Prime lens: A lens with one fixed focal length. Often smaller, sharper and brighter (a wider maximum aperture) than a zoom.
- Zoom lens: A lens with a range of focal lengths, such as 24 to 70mm. More versatile than a prime.
- Kit lens: The zoom sold bundled with a camera body, usually covering wide to short telephoto.
- Fast lens: A lens with a wide maximum aperture, such as f/1.8 or f/2.8, so it gathers a lot of light and allows faster shutter speeds.
- Variable aperture: A zoom whose maximum aperture gets smaller as you zoom in, written as a range such as f/3.5 to 5.6.
- Lens mount: The fitting that attaches a lens to a camera. Each system has its own, which decides which lenses fit.
- Chromatic aberration: Color fringes, often purple or green, along high-contrast edges, caused by a lens focusing different colors at slightly different points.
- Vignetting: Darkening toward the corners of the frame, strongest at wide apertures. It can be corrected in editing or added on purpose.
- Distortion: Straight lines bowing outward (barrel distortion) or inward (pincushion distortion) because of the lens design.
- Lens flare: Streaks, rings or haze caused by bright light bouncing around inside the lens.
- Diffraction: The overall softening that appears at very small apertures, such as f/16 and f/22, as light spreads at the edges of the opening.
Camera and Sensor Terms
- Sensor size: The physical size of the light-sensitive chip. Larger sensors generally handle low light better and make shallow depth of field easier.
- Full frame: A sensor the size of a 35mm film frame, 36 by 24mm.
- APS-C: A smaller sensor format, roughly 23 by 15mm, used in many mirrorless cameras and DSLRs.
- Crop factor: How much smaller a sensor is than full frame, used to compare angles of view. A 50mm lens on a 1.5x crop sensor frames like a 75mm lens on full frame.
- Megapixel: One million pixels. More megapixels allow larger prints and more cropping, but do not by themselves make better pictures.
- Noise: Random speckles of brightness and color, most visible in shadows and at high ISO.
- Mirrorless and DSLR: The two main kinds of interchangeable-lens camera. A DSLR uses a mirror to send the image to an optical viewfinder; a mirrorless camera shows the sensor’s image on an electronic viewfinder or screen.
Light Terms
- Color temperature: The warmth or coolness of light, measured in kelvin (K). Candlelight is around 1900K, household tungsten around 2700 to 3200K, midday sun around 5500K, and open shade 7000K or more.
- Hard light and soft light: Hard light comes from a small or distant source, such as direct sun, and casts crisp shadows. Soft light comes from a large source, such as an overcast sky or a window, and casts gentle ones.
- Golden hour: The time shortly after sunrise and before sunset when sunlight is low, warm and soft.
- Blue hour: The twilight before sunrise and after sunset when the sky turns deep blue and artificial lights balance with it.
- Backlight: Light coming from behind the subject toward the camera. It creates rim light and silhouettes.
- Color cast: An unwanted overall tint, such as orange indoors or blue in shade, usually fixed with white balance.
Composition Terms
- Composition: How the elements in the frame are arranged: placement, balance, lines, space and what you leave out.
- Rule of thirds: Dividing the frame into a 3 by 3 grid and placing key elements on the lines or where they cross.
- Golden ratio: A proportion of about 1 to 1.618 used as a placement guide. Its lines sit slightly closer to the center than the thirds lines.
- Leading lines: Lines in the scene, such as roads, rivers or fences, that guide the eye toward the subject.
- Negative space: Empty area around the subject, used on purpose to isolate it and give the picture room.
- Fill the frame: Moving closer or zooming in until the subject takes up most of the picture.
- Symmetry: A composition where one half mirrors the other, which reads as calm and formal.
File and Editing Terms
- RAW: A file holding the sensor data with minimal processing. It gives the most room to adjust exposure and white balance afterward, but must be processed before sharing.
- JPEG: A compressed image file processed in the camera. Small and ready to share, with less room to edit than RAW. The two are compared in RAW vs JPEG.
- Bit depth: How many tonal steps each color channel can hold. An 8-bit JPEG has 256 levels per channel; RAW files usually hold 12 or 14 bits.
- Resolution: The pixel dimensions of an image, and for prints, how many pixels are spread across each inch.
- Post-processing: Editing a photo after taking it: exposure, color, contrast, cropping and retouching, in software such as Lightroom or Photoshop.
- Contrast: The difference between the light and dark parts of an image.
- Saturation: How intense the colors are, from gray to vivid.
- Highlight recovery: Pulling back detail in bright areas during editing, which works only if the highlights were not fully clipped.
How to Learn These Terms Fast
Definitions stick when you see them happen. Put the camera in Aperture Priority, photograph the same subject at f/2.8 and f/11, and compare the backgrounds: that is depth of field. Then try shutter speeds of 1/1000 and 1/15 on running water: that is motion blur. Ten minutes of this teaches the exposure terms better than an hour of reading. The camera settings cheat sheet gives starting settings for common situations, and the composition cheat sheet does the same for framing.
Want to see aperture, shutter speed and ISO change a real photo? The camera simulator lets you set all three and watch the result.
Photography Terms FAQ
What are the most important photography terms to learn first?
Aperture, shutter speed, ISO, exposure and stop, because together they explain how a camera makes a picture. Add focal length, depth of field, white balance, RAW and composition and you can follow almost any tutorial.
What is the difference between aperture and f-stop?
Aperture is the physical opening in the lens; the f-stop is the number that describes its size. Because the f-number is a ratio, a smaller number such as f/2 means a larger opening than f/16.
What does “stop” mean in photography?
A stop is a doubling or halving of light. It lets you compare aperture, shutter speed and ISO directly: opening up one stop and using a shutter speed one stop faster gives the same exposure.
Where can I find more photography definitions?
This page covers the essentials. The glossary lists every term on the site from A to Z, each linked to its own explanation.