Depth of Field Calculator

Depth of Field (DoF) describes the zone of a photograph where subjects appear acceptably sharp. Everything outside this zone blurs into what photographers call bokeh. Understanding DoF gives you creative control over which parts of your scene appear sharp and which dissolve into a smooth, out-of-focus background.

Core formulas:

Hyperfocal Distance (H) = (f² / (N × c)) + f

Near Focus Limit = (H × D) / (H + D − f)

Far Focus Limit = (H × D) / (H − D + f)

Depth of Field = Far Focus Limit − Near Focus Limit

Variable definitions:

• f: focal length in millimeters (e.g., 50mm, 85mm, 200mm)
• N: f-number (aperture setting: f/1.4, f/2.8, f/8, etc.)
• c: circle of confusion in millimeters (sensor-size dependent)
• D: focusing distance from the camera to your subject
• H: hyperfocal distance: the closest focus point at which infinity is still acceptably sharp

Circle of confusion by sensor size:

Worked example: Camera: Full Frame. Lens: 85mm. Aperture: f/1.8. Subject distance: 8 ft (2.44 m). H = (85² / (1.8 × 0.030)) + 85 = (7,225 / 0.054) + 85 = 133,881 mm ≈ 439 ft Near limit 7.86 ft, far limit 8.14 ft, so the total depth of field is 3.4 inches. That is razor thin. Focus on the near eye and the far ear is already soft.

Creative DoF control:

Real-world DoF ranges at f/2.8 with 85mm (full frame):

• Subject at 3 ft → DoF ≈ 0.7 inches
• Subject at 10 ft → DoF ≈ 8.3 inches
• Subject at 30 ft → DoF ≈ 6.4 feet

Notice how fast that grows. Depth of field scales with roughly the square of the subject distance, so tripling the distance from 10 ft to 30 ft multiplies the sharp zone by about nine, not by three. This is why a head-and-shoulders portrait is a focusing problem and a full-length shot at the same aperture is not.

Put the same 85mm f/2.8 on a Micro Four Thirds body and the 10 ft figure drops to about 4.1 inches, because the smaller circle of confusion is a stricter sharpness test. That runs opposite to the usual “small sensors have more depth of field” shorthand, which only holds when you also change position to keep the framing.

Portrait photographers typically shoot at f/1.4–f/2.8 to isolate subjects against blurred backgrounds. Landscape photographers use f/8–f/16 to keep foreground rocks and distant mountains equally sharp.