Depth of field calculator, with a worked example

In short: Depth of field depends on focal length, f-number, focus distance and the circle of confusion, the sharpness allowance set by the sensor and the output. Focusing at the hyperfocal distance H gives sharpness from about H ÷ 2 to infinity. A 50 mm lens at f/8 with a 0.03 mm circle of confusion has H of about 10.5 metres, so focusing there keeps everything from about 5.2 metres acceptably sharp.

By James Jones, founder of Granary Digital · Updated 5 November 2026

What the calculator does

It tells you the near and far limits of acceptable sharpness for a shot, so you can check the marks before the actor walks onto them. Enter the focal length, the f-number, the focus distance and the circle of confusion. The circle of confusion is the allowance for what counts as sharp. The calculator sets a default for each sensor (0.030 mm for full frame, for example) and you can change it. You can also enter a T-stop instead of an f-number, with the lens light loss in stops, and a shortcut sets the focus distance to the hyperfocal distance. Depth of field depends on the f-number, so a T-stop is converted to an estimated f-number first.

Sensor

Circle of confusion (mm)

Focal length (mm)

Aperture type

f-stop

Focus distance (m)

Shortcut

How this is worked out

Hyperfocal distance: H = f² ÷ (N × c) + f, with focal length f and circle of confusion c in millimetres and f-number N.
Near limit: s × (H − f) ÷ (H + s − 2f). Far limit: s × (H − f) ÷ (H − s), where s is the focus distance. When s is H or more, the far limit is infinity.
Focusing at H puts the near limit at H ÷ 2 and the far limit at infinity.
The circle of confusion is a convention for how large a blur still looks sharp. The defaults below are common working figures (about the sensor diagonal ÷ 1,500 for stills, and the usual cine figures for Super 35 and 16 mm). A bigger value gives more depth of field and a more forgiving result, a smaller value is stricter. For 4K or large-screen work, a smaller figure is safer. Change it in the box above.
Depth of field depends on the f-number, not the T-stop. If you enter a T-stop, the calculator takes the stated light loss off to estimate the f-number. A T-stop number is always a little larger than the f-number.

Sensor	Default circle of confusion (mm)

Reference: Wikipedia, Hyperfocal distance and Depth of field.

The hyperfocal formula

The hyperfocal distance is:

H = f² ÷ (N × c) + f

where f is the focal length, N is the f-number and c is the circle of confusion, all in millimetres. For any practical f-number, the added focal length is small next to the first term. Focusing at H keeps everything from H ÷ 2 out to infinity acceptably sharp. Focusing nearer than H pulls the far limit in, and the near limit moves closer to the camera.

A worked example

A 50 mm lens at f/8 with a circle of confusion of 0.03 mm:

f² is 2,500 mm².
N × c is 8 × 0.03, which is 0.24.
2,500 ÷ 0.24 is about 10,417 mm. Add the 50 mm focal length and H is about 10.5 metres.
Focus at 10.5 metres and the sharp zone starts at about 5.2 metres and runs out to infinity.

If the actor is at 3 metres, focusing at 3 metres gives a much shallower zone. The calculator starts at 50 mm, f/8, 0.03 mm and a focus distance of 3 metres, so it shows the 3 metre case first, and the hyperfocal shortcut shows the other. Compare the two before you choose.

How to use it on a shoot

Choose the lens and the frame from the field of view calculator.
Set the f-number you want for the look, then find the focus distance from the mark on the floor.
Read the near and far limits. If the actor's head or the product falls outside them, change the f-number or the distance.
Check the result on the monitor with the actor in place, not on a chart.

Common mistakes

Treating depth of field as a fixed range for each f-number. It changes with distance and focal length, so a single number on the lens barrel is not enough.
Using a full-frame circle of confusion on a small sensor, which makes the sharp zone look better than it is.
Assuming a longer lens gives more depth of field. From the same position, a longer lens gives less. If you move back to keep the same framing, the depth of field comes out roughly the same, and only the background looks more blurred.
Forgetting that closer subjects have much less depth of field, so a move towards the camera can push the actor out of focus.

Where it fits

Depth of field is one of the four numbers that decide a shot, with the frame, the frame rate and the light. For the shutter and frame rate side, read frame rates and the 180 degree shutter. For the light, three-point lighting and beyond covers how much light the aperture needs.

Sources

Wikipedia, Hyperfocal distance, read 5 November 2026

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Related guides

The picture at the top of this page is an illustration, not a photograph of a client or a real job.

Questions we get asked

Where should I focus for the most depth of field?

Focus at the hyperfocal distance. Everything from about half that distance to infinity is then acceptably sharp.

Does a smaller f-number always give shallow depth of field?

At the same distance and focal length, a smaller f-number gives less depth of field. The distance and the lens length change the result too, so run the numbers for the real shot.

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