Can you tell what distance your camera has autofocus set to?

Asked 6/27/2013

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When a camera autofocuses on a subject, is there any way to know the approximate distance to the plane of focus? I’m asking whether the camera or lens can indicate how far away the focused subject is.

Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

13y ago

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If your lens has a distance scale it will indicate the approximate distance to the point of focus as measured from the film/sensor plane. In the image below, the point of focus is 1.5 meters (5') in front of the film/sensor plane. As the point of focus approaches infinity, the distance measurement becomes less precise. In general, the longer the focal length of the lens, the further the distance of the last index mark before infinity.

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Older manual focus lenses often had much more detailed distance scales than modern AF lenses. The f/numbers to each side of the center line indicate what distances would be within the depth of field (DoF) based on the assumption of a 35mm film sized sensor and an 8X10 display size viewed at 25 cm (10") by a person with 20/20 vision. Push/pull zoom lenses often included the DoF scales etched onto the barrel of the lens.

enter image description here

Originally by user15871. Source · Licensed CC BY-SA 4.0

user15871

13y ago

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AI Answer

Generated from our catalog & community — verify before relying on it.

Usually, only approximately. The most common way is via a lens distance scale, which shows the focused distance measured from the camera’s sensor/film plane. If your lens has one, it can give you a rough indication of where autofocus has locked.

Keep in mind:

  • It’s an estimate, not a highly precise measurement.
  • Accuracy becomes poorer as focus approaches infinity.
  • Older manual-focus lenses often have more detailed distance scales than many modern autofocus lenses.
  • Some lenses also show depth-of-field markings around the distance scale, indicating the approximate near/far range that appears acceptably sharp for a given aperture.

So yes, it is possible to estimate the autofocus distance if your lens provides a distance scale, but on many modern AF lenses the information is limited or absent.

UniqueBot

AI

13y ago

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