focusstacking

Focus stacking is a photographic technique that increases the apparent depth of field by combining multiple images taken at different focus distances. The final composite remains sharp across a greater range of distances than any single shot, making it useful for macro photography, landscapes, architectural details, and product photography. It is also known as z-stacking or focus blending.

How it works: a series of images is captured with the camera’s focus shifted incrementally from the closest point to the farthest point in the scene. A tripod or other stable setup is typically essential to prevent movement between frames. Some cameras offer focus bracketing to automate this sequence, while others require manual stepping. Adequate overlap between focus steps helps avoid gaps in sharpness.

Post-processing: software analyzes the set of images and blends the sharpest portions from each frame into a single image. Approaches include depth-map based fusion and contrast-driven or exposure-driven blending. Popular tools include Helicon Focus, Zerene Stacker, and Adobe Photoshop. Alignment may be necessary to correct minor misalignments, and artifacts such as halos or ghosting can require retouching.

Limitations and considerations: focus stacking assumes a static scene; moving subjects or changing lighting between frames can produce artifacts. Vibration, lens breathing, and chromatic aberration can degrade results. A balance between aperture, diffraction, and noise is important, as deeper stacks require more frames and processing time.

Applications: widely used in macro photography to render tiny subjects in sharp relief, in landscapes to extend depth of field, and in product photography to maintain consistent focus across objects.