Focus Stacking Quiz

Focus stacking uses a series of frames that are identical except for the focus distance, stepping from the nearest to the farthest part of the subject. Software then keeps the sharpest region of each one. Frames at different exposures are for HDR, not focus stacking.

Focus breathing is the slight change in framing when focus is adjusted, because the lens's effective focal length changes as its elements move. In video, a focus pull can look like a small zoom. It has nothing to do with the photographer's breath or the aperture.

A wide landscape with a close foreground often has more depth than one frame can hold sharp, and stopping down far enough brings diffraction softness. Focus stacking blends frames focused near, middle, and far, giving sharpness from the immediate foreground to infinity at the lens's sharpest aperture.

Focus stacking needs software that aligns frames and picks the sharpest areas from each. Photoshop can do it with its auto-align and auto-blend layer tools, and Helicon Focus is a dedicated stacking program. Basic tone sliders in a raw editor cannot combine frames.

Stacking software expects frames that differ only in focus. If the camera moves between shots, the frames no longer line up, so alignment may fail or leave ghosting along edges. A tripod and a remote release keep the framing identical.

Each aperture gives a different depth of field and exposure. If it changes partway through a stack, the frames no longer match in brightness or in how deep each sharp slice is, which causes visible blending errors. The aperture should stay fixed for the whole stack.

Focus stacking with a rail involves physically moving the camera forward in precise increments between frames rather than changing the focus ring. This method ensures the magnification remains constant across all frames, producing a stack that blends without scale mismatches.

Stacking software blends selected sharp regions from each frame at their boundaries. If alignment is imperfect, or if a frame contributes a slightly different perspective, the blend produces a visible fringe or ghost image along edges where the two versions of the subject do not match.

Focus bracketing is a camera feature that shoots a series of frames automatically, shifting focus by a set step between each one. It saves turning the focus ring by hand and keeps the steps even. The frames are then merged in stacking software.

Each frame's zone of sharpness should overlap the next by roughly 20 to 30 percent, so every part of the subject is sharp in at least one frame. With no overlap, thin bands of softness can appear between slices; full overlap simply wastes shots.