Field of view & focal length calculator

Pick any two of focal length, working distance and field of view — we solve for the third and show the angle of view.

Calculate
What do you want to find?
Sensor
Typical active area; pick "Custom" to enter exact dimensions.
mm
mm
Setup
mm
mm
Object to lens.
mm
Width of the object area to capture.
Top view of sensor, lens and object plane at the true horizontal angle of view (distances not to scale), with the object field's proportions.

Details

    How it's calculated

    We use the thin-lens model. Magnification is the ratio of sensor size to object field and relates to focal length f and working distance d (object to lens) as:

    m = sensor width / field width = f / (d − f)

    f = d · m / (1 + m)  ·  d = f · (1 + 1/m)  ·  field = sensor · (d − f) / f

    The angle of view follows from the image distance v = f · (1 + m): angle = 2 · arctan(sensor / 2v). Focused at infinity, v = f.

    Real lenses have separated principal planes, distortion and focus breathing, so the actual distance from the front element differs by a few millimetres. The model is well suited to pre-selection; at close range (working distance below roughly ten times the focal length) we recommend checking against the specific lens's data.

    All results are planning estimates based on simplified models and manufacturer data, without guarantee. Please verify critical values against the manufacturer datasheets before you make a design decision.

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