Hyperfocal distance (GFR)

Focusing the camera at the hyperfocal distance ensures maximum sharpness from half this distance to infinity. The hyperfocal distance is especially useful in landscape photography, and understanding its essence will help you achieve maximum image sharpness by obtaining maximum depth of field — and thus the most detailed final print. Determining the hyperfocal distance for given focal length and aperture can be a challenging task; this chapter explains the method of calculating GFR, clarifies inaccuracies, and provides a GFR calculator. I do not recommend using the calculation result literally, but suggest using it as a guideline.

Hyperfocal distance is well applied when the subject being shot has significant backward extent, or if none of the areas in the image require greater clarity than others. And even in this case, I advise you to either use a stricter definition of «acceptably sharp», or focus a little further to add sharpness to the background. Focus manually using the distance markers on your lens or controlling the distance on your camera's LCD screen if it is indicated there. You can calculate «acceptable sharpness», at which blur is imperceptible with ideal vision for a given print size and viewing distance. Use the hyperfocal distance table at the bottom of the page by changing the vision strength parameter. This will require using a much larger aperture number or focusing at a greater distance to keep the far boundary of DOF at infinity. Using an excessively closed aperture (large number f) can have the opposite effect, as the image will start to blur due to the effect of diffraction. This blur is independent of the object's position relative to the depth of field, and therefore the maximum sharpness in the focal plane can be significantly reduced. For 35 mm and other similar SLR cameras, the effect of diffraction starts to manifest after f/16. For compact digital cameras, there is usually nothing to worry about, as they are often limited to a maximum of f/8.0 or less. Note: the crop factor is also called the focal length multiplier