Find the near and far limits of acceptable sharpness from your lens, aperture, focus distance, and sensor.
Calculator verified • Last updated: August 2026
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Everything between the near and far limits appears acceptably sharp in the photo; a far limit of infinity means everything beyond the near limit, to the horizon, is in focus.
Depth of field starts from the hyperfocal distance — the focus distance beyond which everything up to infinity stays acceptably sharp. It depends on the focal length, the aperture, and the circle of confusion (the largest a point of light can blur on the sensor and still look like a sharp point at normal viewing size).
$$H = \frac{f^2}{N \cdot c} + f$$
Once the hyperfocal distance is known, the near and far limits at any focus distance follow directly:
$$D_n = \frac{H \cdot s}{H + (s - f)} \qquad D_f = \frac{H \cdot s}{H - (s - f)}$$
f: focal length, in millimeters.
N: aperture (f-number).
c: circle of confusion for the sensor size, in millimeters.
s: focus distance, in millimeters.
H: hyperfocal distance, in millimeters.
D_n, D_f: near and far limits of the depth of field, in millimeters.
If the far-limit denominator (H minus (s minus f)) is zero or negative, the far limit is effectively infinite — the focus distance is already at or beyond the hyperfocal distance, so everything from the near limit onward is in focus.
A 50mm lens at f/2.8 on a full-frame camera (circle of confusion 0.03mm), focused at 10 feet (3,048mm): the hyperfocal distance works out to about 29,812mm, or roughly 97.8 feet. Plugging that into the near and far limit formulas gives a near limit around 9.1 feet and a far limit around 11.1 feet — a total depth of field of about 2 feet. Note how shallow that is compared to the 97.8-foot hyperfocal distance: at typical portrait distances, wide apertures produce a noticeably narrow zone of sharpness.
Aperture has the most direct effect — opening up to a wider aperture (a smaller f-number like f/1.8) narrows depth of field, useful for blurring a background behind a subject; closing down to a narrower aperture (a larger f-number like f/11) widens it, useful for landscapes where everything should be sharp. Focal length and focus distance interact too: a longer lens or a closer subject both narrow depth of field even at the same aperture, which is why a telephoto portrait lens produces much softer backgrounds than a wide-angle lens at the same f-number.
Assuming depth of field splits evenly in front of and behind the focus point is a common misconception — in most real shooting situations, roughly one-third of the depth of field falls in front of the focus point and two-thirds falls behind it, though that split shifts closer to even only very near the hyperfocal distance.
Forgetting that sensor size changes the result for the same focal length and aperture is another — a 50mm lens at f/2.8 on a full-frame body has a different depth of field than the same settings on an APS-C body, because the smaller sensor's tighter circle of confusion produces a different hyperfocal distance.
Hyperfocal Distance — the focus distance beyond which everything, out to infinity, appears acceptably sharp.
Circle of Confusion — the largest a point of light can blur on the sensor while still appearing as a sharp point at normal viewing size; smaller sensors use a smaller circle of confusion.
Bokeh — the aesthetic quality of the out-of-focus areas outside the depth of field, distinct from depth of field itself (which measures the sharp zone's size, not how the blur looks).
Depth of field is the range of distances in front of the camera, from the near limit to the far limit, that appear acceptably sharp in a photo. Everything closer than the near limit or farther than the far limit appears progressively blurrier.
A wider aperture (smaller f-number), a longer focal length, and a closer focus distance all make depth of field shallower. A narrower aperture (larger f-number), a shorter focal length, and a farther focus distance all make it deeper.
A smaller sensor uses a smaller circle of confusion (the largest a point of light can blur and still look sharp), because its image gets enlarged more to reach the same output size. This gives smaller sensors inherently deeper depth of field at the same focal length, aperture, and distance.