Photography Glossary

The opening in a lens through which light passes. A wider aperture (lower f-number) lets in more light and creates a shallower depth of field.

The proportional relationship between an image's width and height. Common ratios include 3:2 (standard DSLR), 4:3 (Micro Four Thirds), and 16:9 (widescreen).

A camera system that automatically adjusts the lens to bring a subject into sharp focus. Modern systems use phase-detection or contrast-detection methods.

The aesthetic quality of out-of-focus areas in an image, especially highlights. Smooth, circular bokeh is generally preferred and is influenced by lens design and aperture shape.

Taking multiple shots of the same scene at different exposure settings. Used for HDR photography or to ensure at least one correctly exposed frame.

A shutter setting where the shutter stays open for as long as the shutter button is held down. Used for very long exposures beyond the camera's timed settings.

A shooting mode where the camera takes multiple frames per second in rapid succession. Useful for capturing fast action or selecting the best moment.

A lens defect where different wavelengths of light focus at slightly different points, causing color fringing along high-contrast edges. More common in cheaper lenses and at wide apertures.

The largest blur circle that still appears as a point to the human eye. It determines the boundaries of acceptable sharpness and is used in depth of field calculations.

A measurement in Kelvin that describes the warmth or coolness of a light source. Lower values (2700K) appear warm/orange; higher values (6500K+) appear cool/blue.

The ratio of a camera sensor's diagonal to that of a 35mm full-frame sensor. It affects the effective focal length and field of view.

The range of distance in a scene that appears acceptably sharp. Controlled by aperture, focal length, and subject distance.

The bending of light as it passes through a small aperture, which softens the image. It sets a practical limit on how far you can stop down a lens.

The range between the darkest shadows and brightest highlights a camera can capture in a single exposure. Measured in stops (EV).

A number representing a combination of shutter speed and aperture that produces the same exposure. Each increment of 1 EV doubles or halves the light.

A camera control that overrides the metered exposure, typically in 1/3-stop increments. Positive values brighten the image; negative values darken it.

The relationship between aperture, shutter speed, and ISO. Changing one requires adjusting the others to maintain the same exposure.

A unit of measurement for lens aperture. Each full stop (f/1.4, f/2, f/2.8, f/4...) halves the amount of light passing through the lens.

The distance in millimeters from the optical center of a lens to the sensor when focused at infinity. It determines the angle of view and magnification.

A technique where multiple images focused at different distances are combined in post-processing to achieve greater depth of field than a single exposure allows.

A sensor size equivalent to 35mm film (36 x 24mm). It is the reference standard for focal length and crop factor calculations.

The period shortly after sunrise or before sunset when sunlight is warm, soft, and directional. Highly prized for landscape and portrait photography.

A graph showing the distribution of brightness values in an image. The left side represents shadows, the right side highlights.

The closest focusing distance at which everything from half that distance to infinity is acceptably sharp. Maximizes depth of field for a given aperture.

A system that reduces camera shake blur, either in the lens (OIS) or the camera body (IBIS). Typically provides 3-7 stops of handheld shooting advantage.

A measure of the camera sensor's sensitivity to light. Higher ISO values brighten the image but introduce more noise.

A compressed image file format that applies lossy compression. Smaller file sizes but less editing flexibility compared to RAW.

The unit used to measure color temperature of light. Photographers use Kelvin values to set white balance and match the color of ambient lighting.

The visual effect of a telephoto lens making distant objects appear closer to foreground subjects. It is caused by the long shooting distance, not the lens itself.

A device or camera system that measures the intensity of light to determine proper exposure settings. Cameras use reflected light metering; handheld meters can measure incident light.

A photograph taken with a slow shutter speed, typically seconds or minutes. Used for light trails, smooth water, star trails, and low-light scenes.

Photography that reproduces subjects at or near life-size magnification (1:1 ratio). Requires specialized macro lenses or extension tubes.

A sensor size larger than full frame, typically around 44 x 33mm or 54 x 40mm. Offers higher resolution, shallower depth of field, and greater dynamic range.

One million pixels. The megapixel count of a sensor determines the maximum resolution of images it can capture.

A mirrorless camera system with a sensor measuring 17.3 x 13mm, giving a 2x crop factor. Offers compact bodies and lenses with good image quality.

A DSLR feature that flips the mirror up before the shutter fires, reducing vibration. Used for sharp tripod-mounted shots, especially at slow shutter speeds.

A neutral density filter that reduces the amount of light entering the lens without affecting color. Allows longer exposures or wider apertures in bright conditions.

Random variation in brightness and color in digital images, most visible in shadow areas and at high ISO settings. Can be reduced with noise reduction software.

When an image receives too much light, causing highlights to clip to pure white and lose detail. The opposite of underexposure.

A wide-angle image created by stitching multiple overlapping photographs together. Can cover up to 360 degrees of a scene.

The distance in micrometers between the centers of adjacent pixels on a sensor. Larger pixel pitch generally means better low-light performance.

A filter that reduces reflections and glare from non-metallic surfaces and can deepen blue skies. It works by blocking light waves oscillating in a specific direction.

A lens with a fixed focal length (no zoom). Primes are typically sharper, faster (wider aperture), and lighter than comparable zoom lenses.

An uncompressed or losslessly compressed file format that preserves all sensor data. Offers maximum flexibility in post-processing at the cost of larger file sizes.

A guideline stating that the minimum handheld shutter speed should be 1/(focal length) to avoid camera shake. For a 200mm lens, use at least 1/200s.

A composition guideline that divides the frame into a 3x3 grid. Placing subjects along the lines or at their intersections often creates a more balanced image.

The physical dimensions of a camera's image sensor. Larger sensors capture more light, offer shallower depth of field, and generally produce less noise.

The length of time the camera's shutter is open during an exposure. Faster speeds freeze motion; slower speeds allow motion blur.

Streaks of light created by the apparent motion of stars during a long exposure. Can be captured in a single very long exposure or by stacking multiple shorter frames.

A unit of exposure change representing a doubling or halving of light. Applies to aperture, shutter speed, and ISO equally.

A lens with a focal length longer than about 70mm (full frame equivalent). Telephoto lenses magnify distant subjects and compress perspective.

A lens that can tilt the plane of focus and shift the image circle relative to the sensor. Used for architecture photography and selective focus effects.

When an image receives too little light, causing shadow areas to lose detail and appear noisy. The opposite of overexposure.

A darkening of the corners and edges of an image relative to the center. Can be caused by lens design, filters, or lens hoods, and is sometimes added intentionally in post.

A camera setting that adjusts colors so that white objects appear neutral under different lighting conditions. Can be set automatically or manually using Kelvin values.

A lens with a short focal length (typically below 35mm on full frame) that captures a broader field of view. Often used for landscapes, architecture, and interiors.

A lens with a variable focal length range, allowing the photographer to change framing without moving. Offers versatility at the cost of size, weight, and sometimes sharpness.