Glossary of Photography Terms

The adjustable opening inside a camera lens that controls how much light enters. A wider aperture (lower f-number) allows in more light and creates a shallow depth of field. A narrower aperture (higher f-number) lets in less light and brings more of the image into focus.

The ratio of a photo’s width to its height. Common aspect ratios include 4:3, 3:2, and 16:9. It affects how images display on screens or print sizes.

The arrangement of visual elements in a photo. Good composition helps guide the viewer’s eye and creates balance, focus, and mood. Common techniques include the rule of thirds, leading lines, and framing.

The range in a photo that appears in sharp focus. A shallow depth of field blurs the background (great for portraits), while a deep depth of field keeps most of the image sharp (ideal for landscapes).

Stands for “dots per inch” — a print-specific term that describes how tightly an image’s pixels are packed when printed. Higher DPI usually means better print quality, with 300 DPI being the common standard.

Short for Exchangeable Image File Format. EXIF metadata is hidden information attached to a photo that includes details like date, time, camera model, lens settings, and sometimes GPS location.

The distance (in millimeters) between the lens and the camera sensor. It determines how zoomed in your photo appears. Short focal lengths are wide; long focal lengths are zoomed in or “telephoto.”

A setting that controls your camera’s sensitivity to light. Lower ISO (100–400) is ideal for bright scenes. Higher ISO (800+) is used in low light, but can add grain or noise to the photo.

A file format that preserves all image data from the camera sensor. Unlike JPEG, RAW files are unprocessed and offer more flexibility for editing exposure, color, and detail.

The amount of time the camera’s shutter stays open to expose the sensor to light. Fast shutter speeds (like 1/1000) freeze motion; slow shutter speeds (like 1") create blur or light trails.

A camera setting that adjusts the color temperature of an image to make white objects appear truly white. It helps correct color casts from different lighting conditions (like warm indoor light or cool outdoor shade).

A common compressed image format that reduces file size by discarding some data. It’s widely compatible and good for sharing, but not ideal for heavy editing due to quality loss from compression.

A lossless image format that preserves full image quality and supports transparency. Often used for graphics or images with sharp edges and text. Larger file sizes than JPEG.

High Efficiency Image Coding — a modern image format used by Apple devices. It offers better compression and quality than JPEG but may not be supported on all platforms or apps.

A next-generation image format that offers excellent compression and image quality. It’s smaller and more efficient than JPEG or PNG, but still gaining support across devices and browsers.

Tagged Image File Format — a high-quality, lossless format often used in professional printing and archiving. Produces large files and is not ideal for web sharing.

Visual distortion in a photo, often appearing as grain or speckles. It becomes more noticeable in low-light conditions or at high ISO settings.

A method of reducing the file size of an image by removing or simplifying data. Compression can be lossy (permanently discarding some detail) or lossless (preserving all original information). Smaller files load faster and take up less space, but too much compression can reduce image quality.

A type of compression that permanently removes some image data to reduce file size. Lossy formats, like JPEG or AVIF, aim to discard details the human eye is less likely to notice. Too much lossy compression can lead to visible quality loss or artifacts.

A type of compression that preserves all original image data. Lossless formats, like PNG or TIFF, reduce file size without sacrificing quality. They’re ideal for editing, archiving, or situations where every detail matters.

Unwanted visual distortions caused by excessive lossy compression. Artifacts can appear as blockiness, blurring, halos, or color banding — especially in areas with fine detail, gradients, or sharp edges.

The range between the darkest and brightest parts of an image. A camera with high dynamic range can capture more detail in shadows and highlights without losing information.

A graph showing the distribution of tones in an image — from black (left) to white (right). Helps you evaluate exposure and contrast when editing or shooting manually.

A type of optical imperfection caused by the shape of a lens. It can result in straight lines appearing curved (barrel or pincushion distortion), especially with wide-angle lenses.

The aesthetic quality of the blurred background in a photo. Smooth, soft bokeh is often preferred and depends on lens design and aperture shape.

A type of camera that uses an electronic viewfinder instead of a mirror like in DSLRs. Mirrorless cameras are usually lighter, more compact, and have faster autofocus.

Digital Single-Lens Reflex camera. Uses a mirror system and optical viewfinder to show you the exact scene through the lens. Popular with professionals and hobbyists.

Hidden information stored within a photo file. Includes technical data like shutter speed and ISO, plus sometimes GPS, copyright, or camera details.

One million pixels. Megapixels measure a camera’s resolution. More megapixels can mean sharper images, but sensor size and lens quality matter more in real-world results.