Frontfokus

Frontfokus is a photography term describing a focus error in which the plane of sharpest focus lies in front of the intended subject. The phenomenon is commonly referred to in English as front focus and is most noticeable when using lenses and bodies that are not properly calibrated to each other. It can affect images across various genres, from portraits to macro work, especially at wide apertures.

Causes of frontfokus include misalignment between the camera body and lens, manufacturing tolerances in autofocus systems, and incorrect autofocus settings. Environmental factors such as working distance, atmospheric conditions, and subject movement can also contribute. Some lenses are more prone to front focus due to optical design or decentering problems, and the issue may vary with focal length and aperture.

Detection of frontfokus is typically done with a focused test target or ruler at a stable distance. Shooting at different distances and apertures helps determine whether the sharpness falls short in front of the subject. A common indication is that images appear sharp when slightly re-focused manually, or when stopping down does not fully resolve the issue, since depth of field changes with aperture.

Correction methods include calibrating autofocus using the camera’s AF fine-tune or microadjustment feature (where supported), testing and adjusting for different lenses, and ensuring the lens is properly mounted. If calibration does not resolve the problem, updating camera or lens firmware, having the lens tested for decentering, or servicing may be necessary. Practical workarounds include using manual focus with magnified live view, choosing a smaller aperture to increase tolerance, or focusing on the eyes in portraits.

See also: back focus, focus accuracy, hyperfocal distance.